As talked about in this patch in the kerneldoc of
of_dp_aux_populate_ep_device() and also in the past in commit
a1e3667a98 ("drm/bridge: ti-sn65dsi86: Promote the AUX channel to
its own sub-dev"), it can be difficult for eDP controller drivers to
know when the panel has finished probing when they're using
of_dp_aux_populate_ep_devices().
The ti-sn65dsi86 driver managed to solve this because it was already
broken up into a bunch of sub-drivers. That means we could solve the
problem there by adding a new sub-driver to get the panel. We could
use the traditional -EPROBE_DEFER retry mechansim to handle the case
where the panel hadn't probed yet.
In parade-ps8640 we didn't really solve this. The code just expects
the panel to be ready right away. While reviewing the code originally
I had managed to convince myself it was fine to just expect the panel
right away, but additional testing has shown that not to be the
case. We could fix parade-ps8640 like we did ti-sn65dsi86 but it's
pretty cumbersome (since we're not already broken into multiple
drivers) and requires a bunch of boilerplate code.
After discussion [1] it seems like the best solution for most people
is:
- Accept that there's always at most one device that will probe as a
result of the DP AUX bus (it may have sub-devices, but there will be
one device _directly_ probed).
- When that device finishes probing, we can just have a call back.
This patch implements that idea. We'll now take a callback as an
argument to the populate function. To make this easier to land in
pieces, we'll make wrappers for the old functions. The functions with
the new name (which make it clear that we only have one child) will
take the callback and the functions with the old name will temporarily
wrap.
[1] https://lore.kernel.org/r/CAD=FV=Ur3afHhsXe7a3baWEnD=MFKFeKRbhFU+bt3P67G0MVzQ@mail.gmail.com
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510122726.v3.2.I4182ae27e00792842cb86f1433990a0ef9c0a073@changeid
While working on the DP AUX bus code I found a few small things that
should be fixed. Namely the non-devm version of
of_dp_aux_populate_ep_devices() was missing an export. There was also
an extra blank line in a kerneldoc and a kerneldoc that incorrectly
documented a return value. Fix these.
Fixes: aeb33699fc ("drm: Introduce the DP AUX bus")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510122726.v3.1.Ia91f4849adfc5eb9da1eb37ba79aa65fb3c95a0f@changeid
The DRM_DP_AUX_CHARDEV and DRM_DP_CEC Kconfig symbols enable code that use
DP helper functions, that are only present if CONFIG_DRM_DISPLAY_DP_HELPER
is also enabled.
But these don't select the DRM_DISPLAY_DP_HELPER symbol, meaning that it
is possible to enable any of them without CONFIG_DRM_DISPLAY_DP_HELPER.
That will lead to the following linking errors with the mentioned config:
LD vmlinux.o
MODPOST vmlinux.symvers
MODINFO modules.builtin.modinfo
GEN modules.builtin
LD .tmp_vmlinux.kallsyms1
KSYMS .tmp_vmlinux.kallsyms1.S
AS .tmp_vmlinux.kallsyms1.S
LD .tmp_vmlinux.kallsyms2
KSYMS .tmp_vmlinux.kallsyms2.S
AS .tmp_vmlinux.kallsyms2.S
LD vmlinux
SYSMAP System.map
SORTTAB vmlinux
OBJCOPY arch/arm64/boot/Image
MODPOST modules-only.symvers
ERROR: modpost: "drm_dp_dpcd_write" [drivers/gpu/drm/display/drm_display_helper.ko] undefined!
ERROR: modpost: "drm_dp_read_desc" [drivers/gpu/drm/display/drm_display_helper.ko] undefined!
ERROR: modpost: "drm_dp_dpcd_read" [drivers/gpu/drm/display/drm_display_helper.ko] undefined!
make[1]: *** [scripts/Makefile.modpost:134: modules-only.symvers] Error 1
make[1]: *** Deleting file 'modules-only.symvers'
make: *** [Makefile:1749: modules] Error 2
Besides making these symbols to select CONFIG_DRM_DISPLAY_DP_HELPER, make
them to depend on DRM_DISPLAY_HELPER, since can't be enabled without it.
Note: It seems this has been an issue for a long time but was made easier
to reproduce after the commit 1e0f66420b ("drm/display: Introduce a DRM
display-helper module"). Adding a Fixes: tag just to make sure that this
fix will be picked for stable once the mentioned change also lands there.
Fixes: 1e0f66420b ("drm/display: Introduce a DRM display-helper module")
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220428082244.390859-1-javierm@redhat.com
[Why]
It's reasonable that we receive NAK while doing DP_REMOTE_DPCD_READ.
Downstream device might reply NAK with the reason and source should
react accordingly.
e.g.
1. When downstream device can't handle corresponding message in time,
it then replies NAK as reason been set as DEFER.
2. When multi-function branch-sink device doesn't enumerate virtual
DP peer devices for those multi-function down facing ports. Without
virtual DPCD, branch device might reply NAK with reason as BAD_PARAM
indicating this port can't do aux DPCD read.
It's expected result. Not an error.
[How]
Use drm_dbg_kms() to replace drm_err() when receive NAK.
Changes since v1:
* drm_dp_mst_topology.c file path changed. Folder was rename from
'dp' to 'display'
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[fixed some indenting issues]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220428124944.1683680-1-Wayne.Lin@amd.com
SCDC is the Status and Control Data Channel for HDMI. Move the SCDC
helpers into display/ and split the header into files for core and
helpers. Update all affected drivers. No functional changes.
To avoid the proliferation of Kconfig options, SCDC is part of DRM's
support for HDMI. If necessary, a new option could make SCDC an
independent feature.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-9-tzimmermann@suse.de
Move DRM's HMDI helpers into the display/ subdirectoy and add it
to DRM's display helpers. Update all affected drivers. No functional
changes.
The HDMI helpers were implemented in the EDID and connector code, but
are actually unrelated. With the move to the display-helper library, we
can remove the dependency on drm_edid.{c,h} in some driver's HDMI source
files.
Several of the HDMI helpers remain in EDID code because both share parts
of their implementation internally. With better refractoring of the EDID
code, those HDMI helpers could be moved into the display-helper library
as well.
v3:
* fix Kconfig dependencies (Javier)
v2:
* reduce HDMI helpers to avoid exporting functions (Jani)
* fix include statements (Jani, Javier)
* update Kconfig symbols
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-8-tzimmermann@suse.de
Move DRM's HDCP helper library into the display/ subdirectory and add
it to DRM's display helpers. Split the header file into core and helpers.
Update all affected drivers. No functional changes.
v3:
* fix Kconfig dependencies
v2:
* fix include statements (Jani, Javier)
* update Kconfig symbols
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-7-tzimmermann@suse.de
DSC is the Display Stream Compression standard for DisplayPort. Move
the DSC code into display/ and split the header into files for protocol
core and DRM helpers. Adapt all users of the code. No functional
changes.
To avoid the proliferation of Kconfig options, DSC is part of DRM's
support for DisplayPort. If necessary, a new option could make DSC an
independent feature.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-6-tzimmermann@suse.de
Replace the DP-helper module with a display-helper module. The
support for DisplayPort becomes an internal option that drivers
have to select. Update all related Kconfig and Makefile rules.
Besides the existing code for DisplayPort, the new module will
contain helpers for other video-output standards, such as HDMI.
Drivers will have to select their required video-output helpers.
Linking all display-related code into a single module avoids the
proliferation of small kernel modules.
The module parameters drm_dp_cec_unregister_delay, dp_aux_i2c_speed_khz,
and dp_aux_i2c_transfer_size are moving from the drm_dp_helper namespace
to drm_display_helper.
v2:
* mention module parameters in commit message (Javier)
* distiguish between display module and DP support in Kconfig
* update Makefile rules for DP helpers
* move Kconfig rules into separate file under display/
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-4-tzimmermann@suse.de
Rename dp/ to display/ to account for additional display-related
helpers, such as HDMI. Update all related include statements. No
functional changes.
Various drivers, such as i915 and amdgpu, use similar naming scheme
by putting code for video-output standards into a local display/
directory. The new directory's name is aligned with this convention.
v2:
* update commit message (Javier)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-3-tzimmermann@suse.de
Douglas Anderson