Having GEM buffers backed by non-coherent memory is interesting in the
particular case where it is faster to render to a non-coherent buffer
then sync the data cache, than to render to a write-combine buffer, and
(by extension) much faster than using a shadow buffer. This is true for
instance on some Ingenic SoCs, where even simple blits (e.g. memcpy)
are about three times faster using this method.
Add a 'map_noncoherent' flag to the drm_gem_cma_object structure, which
can be set by the drivers when they create the dumb buffer.
Since this really only applies to software rendering, disable this flag
as soon as the CMA objects are exported via PRIME.
v3: New patch. Now uses a simple 'map_noncoherent' flag to control how
the objects are mapped, and use the new dma_mmap_pages function.
v4: Make sure map_noncoherent is always disabled when creating GEM
objects meant to be used with dma-buf.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210523170415.90410-2-paul@crapouillou.net
The new GEM object function drm_gem_cma_mmap() sets the VMA flags
and offset as in the old implementation and immediately maps in the
buffer's memory pages.
Changing CMA helpers to use the GEM object function allows for the
removal of the special implementations for mmap and gem_prime_mmap
callbacks. The regular functions drm_gem_mmap() and drm_gem_prime_mmap()
are now used.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201123115646.11004-3-tzimmermann@suse.de
As GEM object functions are now mandatory, DRM drivers based on CMA
helpers either set them in their implementation of gem_create_object,
or use the default via drm_gem_cma_create_object_default_funcs().
Simplify this by setting the default CMA object functions for all
objects that don't have any functions of their own. Follows the pattern
of similar code in SHMEM and VRAM helpers. The function
drm_gem_cma_create_object_default_funcs() is redundant and therefore
being removed.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201106131632.6796-1-tzimmermann@suse.de
This patch replaces the vmap/vunmap's use of raw pointers in GEM object
functions with instances of struct dma_buf_map. GEM backends are
converted as well. For most of them, this simply changes the returned type.
TTM-based drivers now return information about the location of the memory,
either system or I/O memory. GEM VRAM helpers and qxl now use ttm_bo_vmap()
et al. Amdgpu, nouveau and radeon use drm_gem_ttm_vmap() et al instead of
implementing their own vmap callbacks.
v7:
* init QXL cursor to mapped BO buffer (kernel test robot)
v5:
* update vkms after switch to shmem
v4:
* use ttm_bo_vmap(), drm_gem_ttm_vmap(), et al. (Daniel, Christian)
* fix a trailing { in drm_gem_vmap()
* remove several empty functions instead of converting them (Daniel)
* comment uses of raw pointers with a TODO (Daniel)
* TODO list: convert more helpers to use struct dma_buf_map
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Christian König <christian.koenig@amd.com>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-7-tzimmermann@suse.de
The function drm_gem_cma_prime_vunmap() is empty. Remove it before
changing the interface to use struct drm_buf_map.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-3-tzimmermann@suse.de
The macro to DRM_GEM_CMA_DRIVER_OPS sets GEM callbacks in struct drm_driver
to their defaults for CMA. A variant of the macro is provided for drivers
that override the default .dumb_create callback. Adapt drivers to the changes.
v4:
* remove parenthesis around dumb_create_func
* fix grammar in commit message
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200605073247.4057-4-tzimmermann@suse.de
Rename the macro to DRM_GEM_CMA_DRIVER_OPS_VMAP to align naming with
SHMEM helpers and drm_gem_cma_prime_import_sg_table_vmap(). An variant of
the macro is provided for drivers that override the default .dumb_create
callback. Adapt drivers to the changes.
v3:
* rename macro to signal implicit vmap on imported buffers
v2:
* provide DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200605073247.4057-3-tzimmermann@suse.de
With all dependencies fixed we can now remove
drmP.h from drm_gem_cma_helper.h.
It is replaced by the include files required,
or forward declarations as appropritate.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190108192939.15255-13-sam@ravnborg.org
This adds functionality to the CMA helper which ensures that the kernel
virtual address is set on the CMA GEM object also for imported buffers.
The drivers have been audited to ensure that none set ->vaddr on imported
buffers, making the conditional dma_buf_vunmap() call in
drm_gem_cma_free_object() safe.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20181110145647.17580-5-noralf@tronnes.org
Cross-subsystem Changes:
- device tree doc for the Mitsubishi AA070MC01 and Tianma TM070RVHG71
panels (Lukasz Majewski) and for a 2nd endpoint on stm32 (Philippe Cornu)
Core Changes:
The most important changes are:
- Add drm_driver .last_close and .output_poll_changed helpers to reduce
fbdev emulation footprint in drivers (Noralf)
- Fix plane clipping in core and for vmwgfx (Ville)
Then we have a bunch of of improvement for print and debug such as the
addition of a framebuffer debugfs file. ELD connector, HDMI and
improvements. And a bunch of misc improvements, clean ups and style
changes and doc updates
[airlied: drop eld bits from amdgpu_dm]
Driver Changes:
- sii8620: filter unsupported modes and add DVI mode support (Maciej Purski)
- rockchip: analogix_dp: Remove unnecessary init code (Jeffy Chen)
- virtio, cirrus: add fb create_handle support to enable screenshots(Lepton Wu)
- virtio: replace reference/unreference with get/put (Aastha Gupta)
- vc4, gma500: Convert timers to use timer_setup() (Kees Cook)
- vc4: Reject HDMI modes with too high of clocks (Eric)
- vc4: Add support for more pixel formats (Dave Stevenson)
- stm: dsi: Rename driver name to "stm32-display-dsi" (Philippe Cornu)
- stm: ltdc: add a 2nd endpoint (Philippe Cornu)
- via: use monotonic time for VIA_WAIT_IRQ (Arnd Bergmann)
* tag 'drm-misc-next-2017-11-30' of git://anongit.freedesktop.org/drm/drm-misc: (96 commits)
drm/bridge: tc358767: add copyright lines
MAINTAINERS: change maintainer for Rockchip drm drivers
drm/vblank: Fix vblank timestamp debugs
drm/via: use monotonic time for VIA_WAIT_IRQ
dma-buf: Fix ifnullfree.cocci warnings
drm/printer: Add drm_vprintf()
drm/edid: Allow HDMI infoframe without VIC or S3D
video/hdmi: Allow "empty" HDMI infoframes
dma-buf/fence: Fix lock inversion within dma-fence-array
drm/sti: Handle return value of platform_get_irq_byname
drm/vc4: Add support for NV21 and NV61.
drm/vc4: Use .pixel_order instead of custom .flip_cbcr
drm/vc4: Add support for DRM_FORMAT_RGB888 and DRM_FORMAT_BGR888
drm: Move drm_plane_helper_check_state() into drm_atomic_helper.c
drm: Check crtc_state->enable rather than crtc->enabled in drm_plane_helper_check_state()
drm/vmwgfx: Try to fix plane clipping
drm/vmwgfx: Use drm_plane_helper_check_state()
drm/vmwgfx: Remove bogus crtc coords vs fb size check
gpu: gma500: remove unneeded DRIVER_LICENSE #define
drm: don't link DP aux i2c adapter to the hardware device node
...
drm_gem_cma_prime_import_sg_table() will fail if the number of entries
in the sg_table > 1. However, you can have a device that uses an IOMMU
engine and can map a discontiguous buffer with multiple entries that
have consecutive sg_dma_addresses, effectively making it contiguous.
Allow for that scenario by testing the entries in the sg_table for
contiguous coverage.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20171110133310.1225-1-Liviu.Dudau@arm.com
This allows the argument to be a const.
The other option was to keep it an inline function and make the argument
a const:
static inline struct drm_gem_cma_object *
to_drm_gem_cma_obj(const struct drm_gem_object *gem_obj)
{
return container_of(gem_obj, struct drm_gem_cma_object, base);
}
This will happily return a non-const pointer to the drm_gem_cma_object
based on a const pointer to the contained drm_gem_object, thus creating
const-safety problems.
There was an attempt to fix the problem in the container_of() macro
itself (see https://lkml.org/lkml/2017/5/19/381) but the patch seems to
have fallen through the cracks. It would require turning this inline
function into a macro.
By making this a macro now, we will benefit from a possible future
enhancement of container_of(). We don't loose type checking by doing
this, container_of() takes care of that.
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171107191348.17555-7-noralf@tronnes.org
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The stub get_unmapped_area() function was actually getting called, so
all of our mmap()s failed.
Cc: Yannick Fertre <yannick.fertre@st.com>
Fixes: 97bf3a9aa6 ("drm/cma: Update DEFINE_DRM_GEM_CMA_FOPS to add get_unmapped_area")
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/20170417233124.18420-1-eric@anholt.net
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Less code ftw.
This converts all drivers except the tinydrm helper module. That one
needs more work, since it gets the THIS_MODULE reference from
tinydrm.ko instead of the actual driver module like it should.
Probably needs a similar trick like I used here with generating the
entire struct with a macro.
Cc: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170308141257.12119-24-daniel.vetter@ffwll.ch
Some SoC without MMU have display driver where a drm/kms driver
could be implemented.
Before doing such kind of thing drm/kms must allow to use mmuless devices.
This patch propose to remove MMU configuration flag and add a cma helper
function to help implementing mmuless display driver
version 4:
- add documentation about drm_gem_cma_get_unmapped_area()
- stub it MMU case
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
[danvet: Use recommended struct member references in kernel-doc.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1483521177-21794-4-git-send-email-benjamin.gaignard@linaro.org
This function is similar to drm_gem_cma_dumb_create() but targetted at
kernel internal users so that they can override the pitch and size
requirements of the dumb buffer.
It is important to make this difference because the IOCTL says that the
pitch and size fields are to be considered outputs and therefore should
not be used in computations of the framebuffer size. Internal users may
still want to use this code to avoid duplication and at the same time
pass on additional, driver-specific restrictions on the pitch and size.
While at it, convert the R-Car DU driver, the single user that overrides
the pitch, to use the new internal helper.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Most of the functions already have the beginnings of kerneldoc comments
but are using the wrong opening marker. Use the correct opening marker
and flesh out the comments so that they can be integrated with the DRM
DocBook document.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
v2: Don't forget git add, noticed by David.
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The following error and warnings will be seen when compiling a C file
which includes <drm/drm_gem_cma_helper.h> but without <drm/drmP.h>
being included before.
include/drm/drm_gem_cma_helper.h:5:24: error: field ‘base’ has incomplete type
include/drm/drm_gem_cma_helper.h: In function ‘to_drm_gem_cma_obj’:
include/drm/drm_gem_cma_helper.h:16:9: warning: initialization from incompatible pointer type [enabled by default]
include/drm/drm_gem_cma_helper.h: At top level:
include/drm/drm_gem_cma_helper.h:24:34: warning: ‘struct drm_mode_create_dumb’ declared inside parameter list [enabled by default]
include/drm/drm_gem_cma_helper.h:24:34: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
include/drm/drm_gem_cma_helper.h:24:34: warning: ‘struct drm_device’ declared inside parameter list [enabled by default]
include/drm/drm_gem_cma_helper.h:24:34: warning: ‘struct drm_file’ declared inside parameter list [enabled by default]
include/drm/drm_gem_cma_helper.h:28:10: warning: ‘struct drm_device’ declared inside parameter list [enabled by default]
include/drm/drm_gem_cma_helper.h:28:10: warning: ‘struct drm_file’ declared inside parameter list [enabled by default]
include/drm/drm_gem_cma_helper.h:35:3: warning: ‘struct drm_device’ declared inside parameter list [enabled by default]
include/drm/drm_gem_cma_helper.h:46:14: warning: ‘struct drm_device’ declared inside parameter list [enabled by default]
Fix them by including <drm/drmP.h> in drm_gem_cma_helper.h.
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
All the gem based kms drivers really want the same function to
destroy a dumb framebuffer backing storage object.
So give it to them and roll it out in all drivers.
This still leaves the option open for kms drivers which don't use GEM
for backing storage, but it does decently simplify matters for gem
drivers.
Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Ben Skeggs <skeggsb@gmail.com>
Reviwed-by: Rob Clark <robdclark@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We can use prime helpers instead.
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Instead of using the dma_buf functionality for GEM CMA, we can use prime
helpers if we can provide low-level hook functions for GEM CMA.
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Add helper to display fb's which can be used directly in drm_info_list:
static struct drm_info_list foo_debugfs_list[] = {
...
{ "fb", drm_fb_cma_debugfs_show, 0 },
};
to display information about CMA fb objects, as well as a
drm_gem_cma_describe() which can be used if the driver bothers to keep
a list of CMA GEM objects.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Many embedded drm devices do not have a IOMMU and no dedicated
memory for graphics. These devices use CMA (Contiguous Memory
Allocator) backed graphics memory. This patch provides helper
functions to be able to share the code. The code technically does
not depend on CMA as the backend allocator, the name has been chosen
because CMA makes for a nice, short but still descriptive function
prefix.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
[Make DRM_GEM_CMA_HELPER a boolean Kconfig option]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>