Commit Graph

168 Commits

Author SHA1 Message Date
Rob Clark bbb1e52402 drm/fb-helper: atomic restore_fbdev_mode()..
Add support for using atomic code-paths for restore_fbdev_mode().

Signed-off-by: Rob Clark <robdclark@gmail.com>
[danvet: Bikeshed comments slightly.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-09-16 11:39:26 -07:00
Daniel Vetter f64c5573d2 drm/fb-helper: Add module option to disable fbdev emulation
Faster than recompiling.

Note that restore_fbdev_mode_unlocked is a bit special and the only
one which returns an error code when fbdev isn't there - i915 needs
that one to not fall over with some additional fbcon related restore
code. Everyone else just ignores the return value or only prints a
DRM_DEBUG level message.

Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-09-08 13:45:50 +02:00
Daniel Vetter b7bdf0a87a drm/fb-helper: Use -errno return in restore_mode_unlocked
Using bool and returning true upon error is very uncommon. Also an int
return value is actually what all the callers which did check it seem
to have expected.

v2: Restore hunk misplaced in a rebase, spotted by Rob.

Cc: Rob Clark <robdclark@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-09-08 13:45:49 +02:00
Maarten Lankhorst cebbb7396b drm/core: Set mode to NULL when connectors in a set drops to 0.
Without this when a MST connector is removed drm_atomic_helper_set_config
can complain about set->mode && !set->num_connectors.

------------[ cut here ]------------
WARNING: CPU: 2 PID: 2403 at drivers/gpu/drm/drm_atomic_helper.c:1673 drm_atomic_helper_set_config+0x22e/0x420()
CPU: 2 PID: 2403 Comm: kms_flip Not tainted 4.2.0-rc5 #4233
Hardware name: NUC5i7RYB, BIOS RYBDWi35.86A.0246.2015.0309.1355 03/09/2015
 ffffffff81ac75e8 ffff88004e4ffbf8 ffffffff81714c34 0000000080000000
 0000000000000000 ffff88004e4ffc38 ffffffff8107bf81 ffff88004e4ffc48
 ffff8800d8ca0690 ffff8800d8d7a080 ffff8800d8cc2290 ffff8800d07bc9f0
Call Trace:
 [<ffffffff81714c34>] dump_stack+0x4f/0x7b
 [<ffffffff8107bf81>] warn_slowpath_common+0x81/0xc0
 [<ffffffff8107c065>] warn_slowpath_null+0x15/0x20
 [<ffffffff813d9e3e>] drm_atomic_helper_set_config+0x22e/0x420
 [<ffffffff813da174>] ? drm_atomic_helper_plane_set_property+0x84/0xc0
 [<ffffffff813ee101>] drm_mode_set_config_internal+0x61/0x100
 [<ffffffff813dc4ed>] restore_fbdev_mode+0xbd/0xe0
 [<ffffffff813de1e4>] drm_fb_helper_restore_fbdev_mode_unlocked+0x24/0x70
 [<ffffffffc0123d11>] intel_fbdev_restore_mode+0x21/0x80 [i915]
 [<ffffffffc014bf69>] i915_driver_lastclose+0x9/0x10 [i915]
 [<ffffffff813e2429>] drm_lastclose+0x29/0x130
 [<ffffffff813e2844>] drm_release+0x314/0x500
 [<ffffffff81194795>] __fput+0xe5/0x1f0
 [<ffffffff811948d9>] ____fput+0x9/0x10
 [<ffffffff810968d8>] task_work_run+0x88/0xb0
 [<ffffffff8107d53f>] do_exit+0x37f/0xa90
 [<ffffffff8127e258>] ? selinux_file_ioctl+0x48/0xc0
 [<ffffffff81277dfe>] ? security_file_ioctl+0x3e/0x60
 [<ffffffff8107ec80>] do_group_exit+0x40/0xa0
 [<ffffffff8107ecef>] SyS_exit_group+0xf/0x10
 [<ffffffff8171bdd7>] entry_SYSCALL_64_fastpath+0x12/0x6a
---[ end trace 0daf358c49351567 ]---

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-11 12:04:19 +02:00
Geert Uytterhoeven 2c4124fdea drm/fb-helper: Move drm_fb_helper_force_kernel_mode() inside #ifdef
If CONFIG_MAGIC_SYSRQ is not set:

    drivers/gpu/drm/drm_fb_helper.c:390:13: warning: 'drm_fb_helper_force_kernel_mode' defined but not used [-Wunused-function]
     static bool drm_fb_helper_force_kernel_mode(void)
		 ^

Move drm_fb_helper_force_kernel_mode() inside the existing #ifdef to fix
this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:13:08 +02:00
Geert Uytterhoeven 3d9e35a92e drm/fb-helper: Clarify drm_fb_helper_restore_fbdev_mode*()
As of commit 5ea1f752ae ("drm: add
drm_fb_helper_restore_fbdev_mode_unlocked()"),
drm_fb_helper_restore_fbdev_mode() is no longer public, and drivers
should call drm_fb_helper_restore_fbdev_mode_unlocked() from their
->lastclose callbacks instead.

Update the documentation to reflect this, and absorb the one liner
drm_fb_helper_restore_fbdev_mode() into its single caller.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:13:08 +02:00
Daniel Vetter dd908c864d drm/fb-helper: Stop using trylocks in force_restore
Since the panic handling is gone this is only used for force-restoring
the fbdev/fbcon from sysrq, and that's done with a work item. No need
any more to do trylocks, we can just do normal locking.

Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-08-06 14:13:01 +02:00
Daniel Vetter c50bfd08d6 drm/fbdev: Return -EBUSY when oopsing
Trying to do anything with kms drivers when oopsing has become a
failing proposition. But since we can end up in the fbdev code simply
due to the console unblanking that's done unconditionally just
removing our panic handler isn't enough. We need to block all fbdev
callbacks when oopsing.

There was already one in the blank handler, but it failed silently.
That makes it impossible for drivers (like i915) who subclass these
functions to figure this out.

Instead consistently return -EBUSY so that everyone knows that we
really don't want to be bothered right now. This also allows us to
remove a pile of FIXMEs from the i915 fbdev code (since due to the
failure code they now won't attempt to grab dangerous locks any more).

Cc: Dave Airlie <airlied@gmail.com>
Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-08-06 14:13:01 +02:00
Archit Taneja fdefa58a50 drm/fb_helper: Create a wrapper for fb_set_suspend
Some drm drivers call fb_set_suspend. Create a drm_fb_helper function
that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v3:
- Fixed kerneldoc errors

v2:
- Added kerneldocs
- Added a check for non-NULL fb_helper before proceeding. This will
  make the helpers work when we have a module param for fbdev emulation
- Follow the drm way of aligning of arguments in func definitions

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:12:56 +02:00
Archit Taneja 742547b73d drm/fb_helper: Create wrappers for blit, copyarea and fillrect funcs
drm drivers that emulate fbdev populate their fb_fillrect, fb_copyarea
and fb_imageblit fb_ops with the help of cfb_* or sys_* fbdev core
helper functions.

Create drm_fb_helper functions that wrap around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v3:
- Fixed kerneldoc errors

v2:
- Added kerneldocs
- Follow the drm way of aligning of arguments in func definitions
- Remove unnecessary checks for non NULL fb_info

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:12:55 +02:00
Archit Taneja cbb1a82e56 drm/fb_helper: Create wrappers for fb_sys_read/write funcs
Some drm drivers populate their fb_ops with fb_sys_read/write fb sysfs
ops.

Create a drm_fb_helper function that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v3:
- Fix kerneldoc errors

v2:
- Added kerneldocs
- Follow the drm way of aligning of arguments in func definitions
- Remove unnecessary checks for non NULL fb_info

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:12:55 +02:00
Archit Taneja 47074ab795 drm/fb_helper: Create a wrapper for unlink_framebuffer
Some drm drivers call unlink_framebuffer. Create a drm_fb_helper function
that wraps around these calls.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly, in order to make fbdev emulation a top level drm
option.

v2:
- Added kerneldocs
- Added a check for non-NULL fb_helper before proceeding. This will
  make the helpers work when we have a module param for fbdev emulation

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:12:54 +02:00
Archit Taneja b8017d6c33 drm/fb_helper: Add drm_fb_helper functions to manage fb_info creation
Every drm driver calls framebuffer_alloc, fb_alloc_cmap,
unregister_framebuffer, fb_dealloc_cmap and framebuffer_release in
order to emulate fbdev support.

Create drm_fb_helper functions that perform the above operations.

This is part of an effort to prevent drm drivers from calling fbdev
functions directly. It also removes repetitive code from drivers.

There are some drivers that call alloc_apertures after framebuffer_alloc
and some that don't. Make the helper always call alloc_apertures. This
would make certain drivers allocate memory for apertures but not use
them. Since it's a small amount of memory, it shouldn't be an issue.

v2:
- Added kerneldocs
- Added a check for non-NULL fb_helper before proceeding. This will
  make the helpers work when we have a module param for fbdev emulation

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-08-06 14:12:54 +02:00
Dave Airlie dcd14dd957 Merge tag 'topic/connector-locking-2015-07-23' of git://anongit.freedesktop.org/drm-intel into drm-next
connector hotplug locking cleanup and fixes to make it save against
atomic. Note that because of depencies this is based on top of the
drm-intel-next pull, so that one needs to go in before this one.

I've also thrown in the mode_group removal on top since it's defunct,
never worked really, no one seems to care and the code can be resurrected
easily.

* tag 'topic/connector-locking-2015-07-23' of git://anongit.freedesktop.org/drm-intel:
  drm: gc now dead mode_group code
  drm: Stop filtering according to mode_group in getresources
  drm: Roll out drm_for_each_{plane,crtc,encoder}
  drm/cma-helper: Fix locking in drm_fb_cma_debugfs_show
  drm: Roll out drm_for_each_connector more
  drm: Amend connector list locking rules
  drm/radeon: Take all modeset locks for DP MST hotplug
  drm/i915: Take all modeset locks for DP MST hotplug
  drm: Check locking in drm_for_each_fb
  drm/i915: Use drm_for_each_fb in i915_debugfs.c
  drm: Check locking in drm_for_each_connector
  drm/fbdev-helper: Grab mode_config.mutex in drm_fb_helper_single_add_all_connectors
  drm/probe-helper: Grab mode_config.mutex in poll_init/enable
  drm: Add modeset object iterators
  drm: Simplify drm_for_each_legacy_plane arguments
2015-07-24 14:30:29 +10:00
Daniel Vetter 169faecadd drm/fbdev-helper: Grab mode_config.mutex in drm_fb_helper_single_add_all_connectors
This is now truly only duct-tape to keep locking checks happy since
calling this function when hpd or polling are already enabled is a
bug. The fbdev helper can't cope with hotplug changes yet at this
point, only after that.

Otoh a bit more robustness in this function can't hurt, and with this
fbdev can actually cope with hotplug changes. And it's also more
consistent with the connector hotadd/remove dp mst needs to do.
Therefore document this as new official behavior.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-07-22 16:25:45 +02:00
Daniel Vetter 6295d607ad drm: Add modeset object iterators
And roll them out across drm_* files. The point here isn't code
prettification (it helps with that too) but that some of these lists
aren't static any more. And having macros will gives us a convenient
place to put locking checks into.

I didn't add an iterator for props since that's only used by a
list_for_each_entry_safe in the driver teardown code.

Search&replace was done with the below cocci spatch. Note that there's
a bunch more places that didn't match and which would need some manual
changes, but I've intentially left these out for this mostly automated
patch.

iterator name drm_for_each_crtc;
struct drm_crtc *crtc;
struct drm_device *dev;
expression head;
@@
- list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+ drm_for_each_crtc (crtc, dev) {
...
}

@@
iterator name drm_for_each_encoder;
struct drm_encoder *encoder;
struct drm_device *dev;
expression head;
@@
- list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+ drm_for_each_encoder (encoder, dev) {
...
}

@@
iterator name drm_for_each_fb;
struct drm_framebuffer *fb;
struct drm_device *dev;
expression head;
@@
- list_for_each_entry(fb, &dev->mode_config.fb_list, head) {
+ drm_for_each_fb (fb, dev) {
...
}

@@
iterator name drm_for_each_connector;
struct drm_connector *connector;
struct drm_device *dev;
expression head;
@@
- list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+ drm_for_each_connector (connector, dev) {
...
}

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-07-22 16:25:45 +02:00
Dave Airlie 6066677cfd drm/fb: drop panic handling
This really doesn't seem to have much chance of working anymore,

esp for irq context, qxl at least tries to talk to the hw,
and waits for irqs, and fails.

with runtime pm and other stuff I think we should just
bail on this for now.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-07-16 11:31:41 +02:00
Jani Nikula be26a66de5 drm/drm: constify all struct drm_*_helper funcs pointers
They are not to be modified.

Generated using the semantic patch:

@@
@@
(
  const struct drm_crtc_helper_funcs *
|
- struct drm_crtc_helper_funcs *
+ const struct drm_crtc_helper_funcs *
)

@@
@@
(
  const struct drm_encoder_helper_funcs *
|
- struct drm_encoder_helper_funcs *
+ const struct drm_encoder_helper_funcs *
)

@@
@@
(
  const struct drm_connector_helper_funcs *
|
- struct drm_connector_helper_funcs *
+ const struct drm_connector_helper_funcs *
)

@@
@@
(
  const struct drm_plane_helper_funcs *
|
- struct drm_plane_helper_funcs *
+ const struct drm_plane_helper_funcs *
)

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-07 18:11:25 +02:00
Daniel Stone f3af5c7ddd drm: fb_helper: Simplify exit condition
mode is always NULL at this point in the function, so make our intention
clear.

Signed-off-by: Daniel Stone <daniels@collabora.com>
[danvet: Stop clearing mode too to enlist gcc in tracking
uninitialized usage. And remove a space while at it.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-03-23 16:22:29 +01:00
Rob Clark 0e3704c94c drm/fb: handle tiled connectors better
We don't want tile 0,0 to artificially constrain the size of the legacy
fbdev device.  Instead when reducing fb_size to be the minimum of all
displays, only consider the rightmost and bottommost tiles.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Tested-by: Hai Li <hali@codeaurora.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-03-11 22:10:11 +01:00
Rob Clark 675c8328db drm/fb: small cleanup
Flip conditional to reduce indentation level of rest of fxn, and use
min/max to make the code clearer.

v2: surface_width -> surface_height typo

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-03-11 22:09:39 +01:00
Linus Torvalds 796e1c5571 Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
Pull drm updates from Dave Airlie:
 "This is the main drm pull, it has a shared branch with some alsa
  crossover but everything should be acked by relevant people.

  New drivers:
     - ATMEL HLCDC driver
     - designware HDMI core support (used in multiple SoCs).

  core:
     - lots more atomic modesetting work, properties and atomic ioctl
       (hidden under option)
     - bridge rework allows support for Samsung exynos chromebooks to
       work finally.
     - some more panels supported

  i915:
     - atomic plane update support
     - DSI uses shared DSI infrastructure
     - Skylake basic support is all merged now
     - component framework used for i915/snd-hda interactions
     - write-combine cpu memory mappings
     - engine init code refactored
     - full ppgtt enabled where execlists are enabled.
     - cherryview rps/gpu turbo and pipe CRC support.

  radeon:
     - indirect draw support for evergreen/cayman
     - SMC and manual fan control for SI/CI
     - Displayport audio support

  amdkfd:
     - SDMA usermode queue support
     - replace suballocator usage with more suitable one
     - rework for allowing interfacing to more than radeon

  nouveau:
     - major renaming in prep for later splitting work
     - merge arm platform driver into nouveau
     - GK20A reclocking support

  msm:
     - conversion to atomic modesetting
     - YUV support for mdp4/5
     - eDP support
     - hw cursor for mdp5

  tegra:
     - conversion to atomic modesetting
     - better suspend/resume support for child devices

  rcar-du:
     - interlaced support

  imx:
     - move to using dw_hdmi shared support
     - mode_fixup support

  sti:
     - DVO support
     - HDMI infoframe support

  exynos:
     - refactoring and cleanup, removed lots of internal unnecessary
       abstraction
     - exynos7 DECON display controller support

  Along with the usual bunch of fixes, cleanups etc"

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (724 commits)
  drm/radeon: fix voltage setup on hawaii
  drm/radeon/dp: Set EDP_CONFIGURATION_SET for bridge chips if necessary
  drm/radeon: only enable kv/kb dpm interrupts once v3
  drm/radeon: workaround for CP HW bug on CIK
  drm/radeon: Don't try to enable write-combining without PAT
  drm/radeon: use 0-255 rather than 0-100 for pwm fan range
  drm/i915: Clamp efficient frequency to valid range
  drm/i915: Really ignore long HPD pulses on eDP
  drm/exynos: Add DECON driver
  drm/i915: Correct the base value while updating LP_OUTPUT_HOLD in MIPI_PORT_CTRL
  drm/i915: Insert a command barrier on BLT/BSD cache flushes
  drm/i915: Drop vblank wait from intel_dp_link_down
  drm/exynos: fix NULL pointer reference
  drm/exynos: remove exynos_plane_dpms
  drm/exynos: remove mode property of exynos crtc
  drm/exynos: Remove exynos_plane_dpms() call with no effect
  drm/i915: Squelch overzealous uncore reset WARN_ON
  drm/i915: Take runtime pm reference on hangcheck_info
  drm/i915: Correct the IOSF Dev_FN field for IOSF transfers
  drm/exynos: fix DMA_ATTR_NO_KERNEL_MAPPING usage
  ...
2015-02-16 15:48:00 -08:00
Rob Clark 2148f18fdb drm: fix fb-helper vs MST dangling connector ptrs (v2)
VT switch back/forth from console to xserver (for example) has potential
to go horribly wrong if a dynamic DP MST connector ends up in the saved
modeset that is restored when switching back to fbcon.

When removing a dynamic connector, don't forget to clean up the saved
state.

v1: original
v2: null out set->fb if no more connectors to avoid making i915 cranky

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1184968
Cc: stable@vger.kernel.org #v3.17+
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-01-30 13:04:17 +10:00
Dave Airlie e4514003c6 Merge tag 'topic/core-stuff-2015-01-23' of git://anongit.freedesktop.org/drm-intel into drm-next
Just flushing out my drm-misc branch, nothing major. Well too old patches
I've dug out from years since a patch from Rob look eerily familiar ;-)

* tag 'topic/core-stuff-2015-01-23' of git://anongit.freedesktop.org/drm-intel:
  drm/probe-helper: clamp unknown connector status in the poll work
  drm/probe-helper: don't lose hotplug event
  next: drm/atomic: Use copy_from_user to copy 64 bit data from user space
  drm: Make drm_read() more robust against multithreaded races
  drm/fb-helper: Propagate errors from initial config failure
  drm: Drop superfluous "select VT_HW_CONSOLE_BINDING"
2015-01-27 08:54:11 +10:00
Thierry Reding 01934c2a69 drm/fb-helper: Propagate errors from initial config failure
Make drm_fb_helper_initial_config() return an int rather than a bool so
that the error can be properly propagated. While at it, update drivers
to propagate errors further rather than just ignore them.

v2:
- cirrus: No cleanup is required, the top-level cirrus_driver_load()
  will do it as part of cirrus_driver_unload() in its cleanup path.
  Reported-by: Fengguang Wu <fengguang.wu@intel.com>

Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
[danvet: Squash in simplification patch from kbuild.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-01-21 14:57:03 +01:00
Rui Wang 9aa609e1a3 drm: fb helper should avoid sleeping in panic context
There are still some places in the fb helper that need to avoid
sleeping in panic context. Here's an example:

[   65.615496] bad: scheduling from the idle thread!
[   65.620747] CPU: 92 PID: 0 Comm: swapper/92 Tainted: G   M        E  3.18.0-rc4-7-default+ #20

[   65.630364] Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS
BRHSXSD1.86B.0056.R01.1409242327 09/24/2014
[   65.641923]  ffff88087f693d80 ffff88087f689878 ffffffff81566db9 0000000000000000
[   65.650226]  ffff88087f693d80 ffff88087f689898 ffffffff810871ff ffff88046eb3e0d0
[   65.658527]  ffff88087f693d80 ffff88087f6898c8 ffffffff8107c1fa 000000017f6898b8
[   65.666830] Call Trace:
[   65.669557]  <#MC>  [<ffffffff81566db9>] dump_stack+0x46/0x58
[   65.675994]  [<ffffffff810871ff>] dequeue_task_idle+0x2f/0x40
[   65.682412]  [<ffffffff8107c1fa>] dequeue_task+0x5a/0x80
[   65.688345]  [<ffffffff810804f3>] deactivate_task+0x23/0x30
[   65.694569]  [<ffffffff81569050>] __schedule+0x580/0x7f0
[   65.700502]  [<ffffffff81569739>] schedule_preempt_disabled+0x29/0x70
[   65.707696]  [<ffffffff8156abb6>] __ww_mutex_lock_slowpath+0xb8/0x162
[   65.714891]  [<ffffffff8156acb3>] __ww_mutex_lock+0x53/0x85
[   65.721125]  [<ffffffffa00b3a5d>] drm_modeset_lock+0x3d/0x110 [drm]
[   65.728132]  [<ffffffffa00b3c2a>] __drm_modeset_lock_all+0x8a/0x120 [drm]
[   65.735721]  [<ffffffffa00b3cd0>] drm_modeset_lock_all+0x10/0x30 [drm]
[   65.743015]  [<ffffffffa01af8bf>] drm_fb_helper_pan_display+0x2f/0xf0 [drm_kms_helper]
[   65.751857]  [<ffffffff8132bd21>] fb_pan_display+0xd1/0x1a0
[   65.758081]  [<ffffffff81326010>] bit_update_start+0x20/0x50
[   65.764400]  [<ffffffff813259f2>] fbcon_switch+0x3a2/0x550
[   65.770528]  [<ffffffff813a01c9>] redraw_screen+0x189/0x240
[   65.776750]  [<ffffffff81322f8a>] fbcon_blank+0x20a/0x2d0
[   65.782778]  [<ffffffff8137d359>] ? erst_writer+0x209/0x330
[   65.789002]  [<ffffffff810ba2f3>] ? internal_add_timer+0x63/0x80
[   65.795710]  [<ffffffff810bc137>] ? mod_timer+0x127/0x1e0
[   65.801740]  [<ffffffff813a0cd8>] do_unblank_screen+0xa8/0x1d0
[   65.808255]  [<ffffffff813a0e10>] unblank_screen+0x10/0x20
[   65.814381]  [<ffffffff812ca0d9>] bust_spinlocks+0x19/0x40
[   65.820508]  [<ffffffff81561ca7>] panic+0x106/0x1f5
[   65.825955]  [<ffffffff8102336c>] mce_panic+0x2ac/0x2e0
[   65.831789]  [<ffffffff812c796a>] ? delay_tsc+0x4a/0x80
[   65.837625]  [<ffffffff81024e1f>] do_machine_check+0xbaf/0xbf0
[   65.844138]  [<ffffffff813365d7>] ? intel_idle+0xc7/0x150
[   65.850166]  [<ffffffff8156f03f>] machine_check+0x1f/0x30
[   65.856195]  [<ffffffff813365d7>] ? intel_idle+0xc7/0x150
[   65.862222]  <<EOE>>  [<ffffffff814283d5>] cpuidle_enter_state+0x55/0x170
[   65.869823]  [<ffffffff814285a7>] cpuidle_enter+0x17/0x20
[   65.875852]  [<ffffffff81097b08>] cpu_startup_entry+0x2d8/0x370
[   65.882467]  [<ffffffff8102fe29>] start_secondary+0x159/0x180

There's __drm_modeset_lock_all() which Daniel Vetter introduced for this
purpose. We can leverage that without reinventing anything. This patch
works with the latest kernel.

Reviewed-by: Rob Clark <robdclark@gmail.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-01-21 09:26:15 +10:00
Dave Airlie b0ee9e7fa5 drm/fb: add support for tiled monitor configurations. (v2)
This adds fbdev/con support for tiled monitors, so that we
only set a mode on the correct half of the monitor, or
span the two halves if needed.

v2: remove unneeded ERROR, fix | vs ||

Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-12-09 09:56:49 +10:00
Dave Airlie e2809c7db8 drm/fb_helper: move deferred fb checking into restore mode (v2)
On MST systems the monitors don't appear when we set the fb up,
but plymouth opens the drm device and holds it open while they
come up, when plymouth finishes and lastclose gets called we
don't do the delayed fb probe, so the monitor never appears on the
console.

Fix this by moving the delayed checking into the mode restore.

v2: Daniel suggested that ->delayed_hotplug is set under
the mode_config mutex, so we should check it under that as
well, while we are in the area.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-12-09 09:56:45 +10:00
Peter Hurley b74c6c92f2 drm: Remove compiler BUG_ON() test
modeset->num_connectors must be 0 to reach the BUG_ON() which tests
for non-zero modeset->num_connectors; remove BUG_ON().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-11-04 09:47:45 +01:00
Dave Airlie a18b29f0c6 Merge tag 'drm-intel-next-2014-09-01' of git://anongit.freedesktop.org/drm-intel into drm-next
drm-intel-next-2014-08-22:
- basic code for execlist, which is the fancy new cmd submission on gen8. Still
  disabled by default (Ben, Oscar Mateo, Thomas Daniel et al)
- remove the useless usage of console_lock for I915_FBDEV=n (Chris)
- clean up relations between ctx and ppgtt
- clean up ppgtt lifetime handling (Michel Thierry)
- various cursor code improvements from Ville
- execbuffer code cleanups and secure batch fixes (Chris)
- prep work for dev -> dev_priv transition (Chris)
- some of the prep patches for the seqno -> request object transition (Chris)
- various small improvements all over

* tag 'drm-intel-next-2014-09-01' of git://anongit.freedesktop.org/drm-intel: (86 commits)
  drm/i915: fix suspend/resume for GENs w/o runtime PM support
  drm/i915: Update DRIVER_DATE to 20140822
  drm: fix plane rotation when restoring fbdev configuration
  drm/i915/bdw: Disable execlists by default
  drm/i915/bdw: Enable Logical Ring Contexts (hence, Execlists)
  drm/i915/bdw: Document Logical Rings, LR contexts and Execlists
  drm/i915/bdw: Print context state in debugfs
  drm/i915/bdw: Display context backing obj & ringbuffer info in debugfs
  drm/i915/bdw: Display execlists info in debugfs
  drm/i915/bdw: Disable semaphores for Execlists
  drm/i915/bdw: Make sure gpu reset still works with Execlists
  drm/i915/bdw: Don't write PDP in the legacy way when using LRCs
  drm/i915: Track cursor changes as frontbuffer tracking flushes
  drm/i915/bdw: Help out the ctx switch interrupt handler
  drm/i915/bdw: Avoid non-lite-restore preemptions
  drm/i915/bdw: Handle context switch events
  drm/i915/bdw: Two-stage execlist submit process
  drm/i915/bdw: Write the tail pointer, LRC style
  drm/i915/bdw: Implement context switching (somewhat)
  drm/i915/bdw: Emission of requests with logical rings
  ...

Conflicts:
	drivers/gpu/drm/i915/i915_drv.c
2014-09-03 08:30:48 +10:00
Dave Airlie d5a0f2e7be Merge tag 'drm-intel-next-2014-08-08' of git://anongit.freedesktop.org/drm-intel into drm-next
- Setting dp M2/N2 values plus state checker support (Vandana Kannan)
- chv power well support (Ville)
- DP training pattern 3 support for chv (Ville)
- cleanup of the hsw/bdw ddi pll code, prep work for skl (Damien)
- dsi video burst mode support (Shobhit)
- piles of other chv fixes all over (Ville et. al.)
- cleanup of the ddi translation tables setup code (Damien)
- 180 deg rotation support (Ville & Sonika Jindal)

* tag 'drm-intel-next-2014-08-08' of git://anongit.freedesktop.org/drm-intel: (59 commits)
  drm/i915: Update DRIVER_DATE to 20140808
  drm/i915: No busy-loop wait_for in the ring init code
  drm/i915: Add sprite watermark programming for VLV and CHV
  drm/i915: Round-up clock and limit drain latency
  drm/i915: Generalize drain latency computation
  drm/i915: Free pending page flip events at .preclose()
  drm/i915: clean up PPGTT checking logic
  drm/i915: Polish the chv cmnlane resrt macros
  drm/i915: Hack to tie both common lanes together on chv
  drm/i915: Add cherryview_update_wm()
  drm/i915: Update DDL only for current CRTC
  drm/i915: Parametrize VLV_DDL registers
  drm/i915: Fill out the FWx watermark register defines
  drm: Resetting rotation property
  drm/i915: Add rotation property for sprites
  drm: Add rotation_property to mode_config
  drm/i915: Make intel_plane_restore() return an error
  drm/i915: Add 180 degree sprite rotation support
  drm/i915: Introduce a for_each_intel_encoder() macro
  drm/i915: Demote the DRRS messages to debug messages
  ...
2014-08-26 09:04:32 +10:00
Thomas Wood 3a5f87c286 drm: fix plane rotation when restoring fbdev configuration
Make sure plane rotation is reset correctly when restoring the fbdev
configuration by using drm_mode_plane_set_obj_prop which calls the
driver's set_property callback.

The rotation reset feature was introduced in commit 9783de2 (drm:
Resetting rotation property) and the callback issue was originally
addressed in a previous version of the patch, but the fix was not
present in the final version.

v2: Fix documentation warning
    Add some more details to the commit message (Daniel Vetter)

Testcase: igt/kms_rotation_crc
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82236
Cc: Sonika Jindal <sonika.jindal@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thomas Wood <thomas.wood@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-08-20 17:19:27 +02:00
Damien Lespiau 14f476fa24 drm: Use the type of the array element when reallocating
Static analysers find it 'suspicious', that we're trying to allocate memory for
elements of size sizeof(struct drm_fb_helper_connector) when the array is
defined as struct drm_fb_helper_connector **.

Use sizeof(struct drm_fb_helper_connector *) instead.

Note that the structure being defined as:

struct drm_fb_helper_connector {
	struct drm_connector *connector;
};

This was still doing the right thing, but may not in the future if
additional fields are added.

Cc: Todd Previte <tprevite@gmail.com>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-08-14 21:24:30 +02:00
Daniel Vetter cb597bb3a2 drm: trylock modest locking for fbdev panics
In the fbdev code we want to do trylocks only to avoid deadlocks and
other ugly issues. Thus far we've only grabbed the overall modeset
lock, but that already failed to exclude a pile of potential
concurrent operations. With proper atomic support this will be worse.

So add a trylock mode to the modeset locking code which attempts all
locks only with trylocks, if possible. We need to track this in the
locking functions themselves and can't restrict this to drivers since
driver-private w/w mutexes must be treated the same way.

There's still the issue that other driver private locks aren't handled
here at all, but well can't have everything. With this we will at
least not regress, even once atomic allows lots of concurrent kms
activity.

Aside: We should move the acquire context to stack-based allocation in
the callers to get rid of that awful WARN_ON(kmalloc_failed) control
flow which just blows up when memory is short. But that's material for
separate patches.

v2:
- Fix logic inversion fumble in the fb helper.
- Add proper kerneldoc.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-08-08 17:47:01 +02:00
Sonika Jindal 9783de2096 drm: Resetting rotation property
Reset rotation property to 0.

v2: Resetting after disabling the plane

Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-08-08 17:43:53 +02:00
Chris Wilson eaf99c749d drm: Perform cmdline mode parsing during connector initialisation
i915.ko has a custom fbdev initialisation routine that aims to preserve
the current mode set by the BIOS, unless overruled by the user. The
user's wishes are determined by what, if any, mode is specified on the
command line (via the video= parameter). However, that command line mode
is first parsed by drm_fb_helper_initial_config() which is called after
i915.ko's custom initial_config() as a fallback method. So in order for
us to honour it, we need to move the cmdline parser earlier. If we
perform the connector cmdline parsing as soon as we initialise the
connector, that cmdline mode and forced status is then available even if
the fbdev helper is not compiled in or never called.

We also then expose the cmdline user mode in the connector mode lists.

v2: Rebase after connector->name upheaval.

v3: Adapt mga200 to look for the cmdline mode in the new place. Nicely
simplifies things while at that.

v4: Fix checkpatch.

v5: Select FB_CMDLINE to adapt to the changed fbdev patch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=73154
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org> (v2)
Cc: dri-devel@lists.freedesktop.org
Cc: Julia Lemire <jlemire@matrox.com>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-08-06 14:50:12 +02:00
Dave Airlie 65c2a89c30 drm/fb_helper: allow adding/removing connectors later
This is required to get fbcon probing to work on new connectors,
callers should acquire the mode config lock before calling these.

Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-07-08 11:39:45 +10:00
Thierry Reding 10a2310265 drm: Introduce drm_fb_helper_prepare()
To implement hotplug detection in a race-free manner, drivers must call
drm_kms_helper_poll_init() before hotplug events can be triggered. Such
events can be triggered right after any of the encoders or connectors
are initialized. At the same time, if the drm_fb_helper_hotplug_event()
helper is used by a driver, then the poll helper requires some parts of
the FB helper to be initialized to prevent a crash.

At the same time, drm_fb_helper_init() requires information that is not
necessarily available at such an early stage (number of CRTCs and
connectors), so it cannot be used yet.

Add a new helper, drm_fb_helper_prepare(), that initializes the bare
minimum needed to allow drm_kms_helper_poll_init() to execute and any
subsequent hotplug events to be processed properly.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-07-08 11:31:28 +10:00
Daniel Vetter 50c3dc970a drm/fb-helper: Fix hpd vs. initial config races
Some drivers need to be able to have a perfect race-free fbcon setup.
Current drivers only enable hotplug processing after the call to
drm_fb_helper_initial_config which leaves a tiny but important race.

This race is especially noticable on embedded platforms where the
driver itself enables the voltage for the hdmi output, since only then
will monitors (after a bit of delay, as usual) respond by asserting
the hpd pin.

Most of the infrastructure is already there with the split-out
drm_fb_helper_init. And drm_fb_helper_initial_config already has all
the required locking to handle concurrent hpd events since

commit 53f1904bce
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Mar 20 14:26:35 2014 +0100

    drm/fb-helper: improve drm_fb_helper_initial_config locking

The only missing bit is making drm_fb_helper_hotplug_event save
against concurrent calls of drm_fb_helper_initial_config. The only
unprotected bit is the check for fb_helper->fb.

With that drivers can first initialize the fb helper, then enabel
hotplug processing and then set up the initial config all in a
completely race-free manner. Update kerneldoc and convert i915 as a
proof of concept.

Feature requested by Thierry since his tegra driver atm reliably boots
slowly enough to misses the hotplug event for an external hdmi screen,
but also reliably boots to quickly for the hpd pin to be asserted when
the fb helper calls into the hdmi ->detect function.

Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-07-08 11:31:13 +10:00
Liu Ying 2a8c6edfd2 drm/fb-helper: Remove unnecessary list empty check in drm_fb_helper_debug_enter()
The following list empty check is unnecessary because we would still do nothing
real and return 'val' if my_list is empty.

if (list_empty(&my_list))
	return val;

list_for_each_entry(pos, &my_list, member) {
	...
}

return val;

This patch removes the unnecessary check in drm_fb_helper_debug_enter().

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-06-19 10:13:46 +02:00
Liu Ying 30bfa4eec7 drm/fb-helper: Redundant info->fix.type_aux setting in drm_fb_helper_fill_fix()
The variable info->fix.type_aux is set to zero twice in the function
drm_fb_helper_fill_fix().  This patch removes one redundant.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-06-19 09:16:27 +02:00
Rob Clark 5ea1f752ae drm: add drm_fb_helper_restore_fbdev_mode_unlocked()
All drm_fb_helper_restore_fbdev_mode() call sites, save one, do the same
locking.  Simplify this into drm_fb_helper_restore_fbdev_mode_unlocked().

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-06-05 10:02:40 +10:00
Rob Clark 51fd371bba drm: convert crtc and connection_mutex to ww_mutex (v5)
For atomic, it will be quite necessary to not need to care so much
about locking order.  And 'state' gives us a convenient place to stash a
ww_ctx for any sort of update that needs to grab multiple crtc locks.

Because we will want to eventually make locking even more fine grained
(giving locks to planes, connectors, etc), split out drm_modeset_lock
and drm_modeset_acquire_ctx to track acquired locks.

Atomic will use this to keep track of which locks have been acquired
in a transaction.

v1: original
v2: remove a few things not needed until atomic, for now
v3: update for v3 of connection_mutex patch..
v4: squash in docbook
v5: doc tweaks/fixes

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-06-05 09:54:33 +10:00
Jani Nikula 259338205c drm: replace drm_get_connector_name() with direct name field use
Generated using semantic patch:

@@
expression E;
@@

- drm_get_connector_name(E)
+ E->name

[airlied: regenerated]

Acked-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-06-04 13:17:41 +10:00
Thierry Reding 83c617c590 drm/fb: Fix typos
Fix a few trivial typos in the framebuffer helper documentation.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-04-29 12:33:17 +02:00
Thierry Reding b77f0765fd drm: Try to acquire modeset lock on panic or sysrq
Commit 62ff94a549 "drm/crtc-helper: remove LOCKING from kerneldoc"
causes drm_helper_crtc_in_use() and drm_helper_encoder_in_use() to
complain loudly during a kernel panic or sysrq processing. This is
caused by nobody acquiring the modeset lock in these code paths.

This patch fixes this by trying to acquire the modeset lock for each
FB helper that's forced to kernel mode. If the lock can't be acquired,
it's likely that somebody else is performing a modeset. However, doing
another modeset concurrently might make things even worse, so the safe
option is to simply bail out in that case.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-04-29 12:24:12 +02:00
Takashi Iwai c683f427bd drm: Prefer noninterlace cmdline mode unless explicitly specified
Currently drm_pick_cmdline_mode() doesn't care about the interlace
when the given mode line has no "i" suffix.  That is, when there are
multiple entries for the same resolution, an interlace mode might be
picked up just depending on the assigned order, and there is no way to
exclude it.

This patch changes the logic for the mode selection, to prefer the
noninterlace mode unless the interlace mode is explicitly given.
When no matching mode is found, it still tries the interlace mode as
fallback.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-04-04 10:07:03 +10:00
Matt Roper f4510a2752 drm: Replace crtc fb with primary plane fb (v3)
Now that CRTC's have a primary plane, there's no need to track the
framebuffer in the CRTC.  Replace all references to the CRTC fb with the
primary plane's fb.

This patch was generated by the Coccinelle semantic patching tool using
the following rules:

        @@ struct drm_crtc C; @@
        -   (C).fb
        +   C.primary->fb

        @@ struct drm_crtc *C; @@
        -   (C)->fb
        +   C->primary->fb

v3: Generate patch via coccinelle.  Actual removal of crtc->fb has been
    moved to a subsequent patch.

v2: Fixup several lingering crtc->fb instances that were missed in the
    first patch iteration.  [Rob Clark]

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
2014-04-01 20:18:28 -04:00
Matt Roper e27dde3e1c drm: Add support for multiple plane types (v2)
The DRM core currently only tracks "overlay"-style planes.  Start
refactoring the plane handling to allow other plane types (primary and
cursor) to also be placed on the DRM plane list.

v2: Add drm_for_each_legacy_plane() iterator to smooth transition
    of drivers with plane loops.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
2014-04-01 19:13:07 -04:00
Daniel Vetter 53f1904bce drm/fb-helper: improve drm_fb_helper_initial_config locking
The locking in drm_fb_helper_initial_config is a bit troublesome for a
few reasons:

- We can't just wrap the entire function up into modeset locks since
  the fbdev registration might call down into fbcon code, which then
  through our ->set_par implementation needs to be able to grab all
  modeset locks. So we'd have a neat deadlock.

- This implies though that all current callers don't hold any modeset
  locks by necessity, so we have free reign to grab any modeset locks
  we need to grab.

- The private state of the fbdev helper doesn't need any protection
  through locks, since once we have the fbdev registered it is mostly
  invariant or protected through the modeset locking in ->set_par and
  other callbacks. We can fully rely on driver having non-racy setup
  sequences here. For the initial config computation we actually may
  not grab locks since drivers which provide their own magic sauce
  (like i915) might need to grab locks themselves.

- We should grab locks though when we probe outputs. Currently there's
  not much risk, but already now userspace could start poking at sysfs
  files and so probe concurrently. I expect that in the future driver
  init will be much more async, and since probing is really
  time-consuming this is a prime candidate.

- We must not hold any crtc->mutex locks while calling probe functions
  since those might need to lock a crtc for e.g. load detection. i915
  is such a driver.

Also it's the probing calls which hit upon piles of new locking
asserts I've recently added in

commit 62ff94a549
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jan 23 22:18:47 2014 +0100

    drm/crtc-helper: remove LOCKING from kerneldoc

and

commit 6395138505
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jan 23 15:14:15 2014 +0100

    drm/doc: Repleace LOCKING kerneldoc sections in drm_modes.c

Hence the right fix is to grab the mode_config mutex, but only that
and only right around the probe calls.

It seems to be sufficient to shut up all the locking WARNINGs I see on
i915 and nouveau in drm_fb_helper_initial_config.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-03-22 08:03:41 +10:00