linux.git/drivers/gpu/drm/tiny/repaper.c, branch v6.18.21

drm/repaper: Do not access GEM-DMA vaddr directly

2025-08-11T16:49:05+00:00

Use DRM's shadow-plane helper to map and access the GEM object's buffer
within kernel address space. Encapsulates the vmap logic in the GEM-DMA
helpers.

The repaper driver currently reads the vaddr field from the GME buffer
object directly. This only works because GEM code 'automagically' sets
vaddr.

Shadow-plane helpers perform the same steps, but with correct abstraction
behind drm_gem_vmap(). The shadow-plane state provides the buffer address
in kernel address space and the format-conversion state.

v2:
- fix typo in commit description

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250627152422.8399-1-tzimmermann@suse.de

drm/repaper: fix integer overflows in repeat functions

2025-02-25T00:43:23+00:00

There are conditions, albeit somewhat unlikely, under which right hand
expressions, calculating the end of time period in functions like
repaper_frame_fixed_repeat(), may overflow.

For instance, if 'factor10x' in repaper_get_temperature() is high
enough (170), as is 'epd->stage_time' in repaper_probe(), then the
resulting value of 'end' will not fit in unsigned int expression.

Mitigate this by casting 'epd->factored_stage_time' to wider type before
any multiplication is done.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 3589211e9b03 ("drm/tinydrm: Add RePaper e-ink driver")
Cc: stable@vger.kernel.org
Signed-off-by: Nikita Zhandarovich 
Signed-off-by: Alex Lanzano 
Link: https://patchwork.freedesktop.org/patch/msgid/20250116134801.22067-1-n.zhandarovich@fintech.ru

drm: remove driver date from struct drm_driver and all drivers

2024-12-05T10:35:42+00:00

We stopped using the driver initialized date in commit 7fb8af6798e8
("drm: deprecate driver date") and (eventually) started returning "0"
for drm_version ioctl instead.

Finish the job, and remove the unused date member from struct
drm_driver, its initialization from drivers, along with the common
DRIVER_DATE macros.

v2: Also update drivers/accel (kernel test robot)

Reviewed-by: Javier Martinez Canillas 
Acked-by: Alex Deucher 
Acked-by: Simon Ser 
Acked-by: Jeffrey Hugo 
Acked-by: Lucas De Marchi 
Acked-by: Dmitry Baryshkov  # msm
Reviewed-by: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/1f2bf2543aed270a06f6c707fd6ed1b78bf16712.1733322525.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula

drm/client: Move public client header to clients/ subdirectory

2024-11-15T08:42:13+00:00

Move the public header file drm_client_setup.h to the clients/
subdirectory and update all drivers. No functional changes.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Jocelyn Falempe 
Link: https://patchwork.freedesktop.org/patch/msgid/20241108154600.126162-3-tzimmermann@suse.de

drm/repaper: Run DRM default client setup

2024-09-26T07:31:27+00:00

Call drm_client_setup() to run the kernel's default client setup
for DRM. Set fbdev_probe in struct drm_driver, so that the client
setup can start the common fbdev client.

v5:
- select DRM_CLIENT_SELECTION

Signed-off-by: Thomas Zimmermann 
Cc: "Noralf Trønnes" 
Acked-by: Noralf Trønnes 
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-37-tzimmermann@suse.de

drm/tiny/repaper: Use fbdev-dma

2024-05-02T09:33:31+00:00

Implement fbdev emulation with fbdev-dma. Fbdev-dma now supports
damage handling, which is required by repaper. Avoids the overhead of
fbdev-generic's additional shadow buffering. No functional changes.

Signed-off-by: Thomas Zimmermann 
Cc: "Noralf Trønnes" 
Acked-by: Noralf Trønnes 
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-40-tzimmermann@suse.de

drm/format-helper: Pass format-conversion state to helpers

2023-11-14T09:16:53+00:00

Pass an instance of struct drm_format_conv_state to DRM's format
conversion helpers. Update all callers.

Most drivers can use the format-conversion state from their shadow-
plane state. The shadow plane's destroy function releases the
allocated buffer. Drivers will later be able to allocate a buffer
of appropriate size in their plane's atomic_check code.

The gud driver uses a separate thread for committing updates. For
now, the update worker contains its own format-conversion state.

Images in the format-helper tests are small. The tests preallocate
a static page for the temporary buffer. Unloading the module releases
the memory.

v6:
	* update patch for ssd132x support
v5:
	* avoid using unusupported shadow-plane state in repaper (Noralf)
	* fix documentation (Noralf, kernel test robot)
v3:
	* store buffer in shadow-plane state (Javier, Maxime)
	* replace ARRAY_SIZE() with sizeof() (Jani)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Tested-by: Javier Martinez Canillas  # ssd130x
Cc: Noralf Trønnes 
Cc: Javier Martinez Canillas 
Cc: Gerd Hoffmann 
Cc: David Lechner 
Link: https://patchwork.freedesktop.org/patch/msgid/20231009141018.11291-4-tzimmermann@suse.de

drm/repaper: fix -Wvoid-pointer-to-enum-cast warning

2023-08-25T11:13:20+00:00

When building with clang 18 I see the following warning:
|       drivers/gpu/drm/tiny/repaper.c:952:11: warning: cast to smaller integer
|       type 'enum repaper_model' from 'const void *' [-Wvoid-pointer-to-enum-cast]
|         952 |                 model = (enum repaper_model)match;
|

This is due to the fact that `match` is a void* while `enum repaper_model`
has the size of an int.

Add uintptr_t cast to silence clang warning while also keeping enum cast
for readability and consistency with other `model` assignment just a
few lines below:
|       model = (enum repaper_model)spi_id->driver_data;

Link: https://github.com/ClangBuiltLinux/linux/issues/1910
Reported-by: Nathan Chancellor 
Signed-off-by: Justin Stitt 
Signed-off-by: Noralf Trønnes 
Link: https://patchwork.freedesktop.org/patch/msgid/20230816-void-drivers-gpu-drm-tiny-repaper-v1-1-9d8d10f0d52f@google.com

drm/repaper: Reduce temporary buffer size in repaper_fb_dirty()

2023-07-29T19:22:02+00:00

As the temporary buffer is no longer used to store 8-bit grayscale data,
its size can be reduced to the size needed to store the monochrome
bitmap data.

Fixes: 24c6bedefbe71de9 ("drm/repaper: Use format helper for xrgb8888 to monochrome conversion")
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Javier Martinez Canillas 
Signed-off-by: Javier Martinez Canillas 
Link: https://patchwork.freedesktop.org/patch/msgid/20220317081830.1211400-6-geert@linux-m68k.org

drm/fb-helper: Move generic fbdev emulation into separate source file

2022-11-05T16:12:04+00:00

Move the generic fbdev implementation into its own source and header
file. Adapt drivers. No functional changes, but some of the internal
helpers have been renamed to fit into the drm_fbdev_ naming scheme.

v3:
	* rename drm_fbdev.{c,h} to drm_fbdev_generic.{c,h}
	* rebase onto vmwgfx changes
	* rebase onto xlnx changes
	* fix include statements in amdgpu

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://patchwork.freedesktop.org/patch/msgid/20221103151446.2638-22-tzimmermann@suse.de