linux-stable.git/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c, branch linux-rolling-stable

drm/sysfb: Return errno code from drm_sysfb_get_visible_size()

2026-08-03T09:25:40+00:00

commit 7bab0f09d753f098977bbba3955d694c2e2c25da upstream.

Change the return type of drm_sysfb_get_visible_size() to s64 so
that it returns a possible errno code from _get_validated_size0().
Fix callers to handle the errno code.

The currently returned unsigned type converts an errno code to a
very large size value, which drivers interpret as visible size of
the system framebuffer. Later efforts to reserve the framebuffer
resource fail.

The bug has been present since efidrm and vesadrm got merged. It
was then part of each driver.

Signed-off-by: Thomas Zimmermann 
Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays")
Reviewed-by: Javier Martinez Canillas 
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v6.16+
Link: https://patch.msgid.link/20260618084327.46567-4-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman

drm/sysfb: Avoid possible truncation with calculating visible size

2026-08-03T09:25:40+00:00

commit b771974988ec7ce077a7246fa0fa588c246fe581 upstream.

Calculating the visible size of the system framebuffer can result in
truncation of the result. The calculation uses 32-bit arithmetics,
which can overflow if the values for height and stride are large. Fix
the issue by multiplying with mul_u32_u32().

Signed-off-by: Thomas Zimmermann 
Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays")
Reported-by: Sashiko 
Closes: https://lore.kernel.org/dri-devel/20260617114027.1F2A71F000E9@smtp.kernel.org/
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v6.16+
Reviewed-by: Javier Martinez Canillas 
Link: https://patch.msgid.link/20260618084327.46567-3-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman

drm/sysfb: Avoid truncating maximum stride

2026-08-03T09:25:39+00:00

commit 9206b22fb959f4a9cf1921f34aed0df1dcb1ab04 upstream.

Passing a maximum as 64-bit type to drm_sysfb_get_validated_int0()
can truncate the value to 32 bits. Use drm_sysfb_get_validated_size0(),
which uses 64-bit arithmetics. Then test the returned stride against
the limits of int to avoid truncations in the returned value. A valid
stride is in the range of [1, INT_MAX] inclusive.

Signed-off-by: Thomas Zimmermann 
Reported-by: Sashiko 
Closes: https://lore.kernel.org/dri-devel/20260617114016.5A5991F000E9@smtp.kernel.org/
Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays")
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v6.16+
Reviewed-by: Javier Martinez Canillas 
Link: https://patch.msgid.link/20260618084327.46567-5-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman

drm/sysfb: Do not page-align visible size of the framebuffer

2026-08-03T09:25:39+00:00

commit 134844856c399bfa9462a159dcf860bfdb748055 upstream.

Only return the actually visible size of the system framebuffer in
drm_sysfb_get_visible_size_si(). Drivers use this size value for
reserving access to framebuffer memory. Increasing the value can
make later attempts to do so fail.

Signed-off-by: Thomas Zimmermann 
Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays")
Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays")
Reviewed-by: Javier Martinez Canillas 
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v6.16+
Link: https://patch.msgid.link/20260618084327.46567-2-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman

drm/sysfb: Generalize pixel-format matching

2026-02-20T13:38:23+00:00

Provide drm_sysfb_get_format(), a helper that finds a specific DRM
format from a list of pixel formats. The new function builds upon
drm_sysfb_get_format_si(), which finds the DRM format from a given
instance of struct screen_info. Now get the screen_info's pixel format
in the caller. Allows for matching pixel formats in drivers without
screen_info.

Convert the callers in efidrm and vesadrm to the new interface.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Acked-by: Julius Werner 
Link: https://patch.msgid.link/20260217155836.96267-11-tzimmermann@suse.de

drm/sysfb: Find screen_info format with helpers

2025-08-26T07:54:17+00:00

Convert drm_sysfb_get_format_si() to lookup the screen_info color
format as struct pixel_format with screen_info_pixel_format(). Then
search the list of given formats for the screen_info format with
pixel_format_equal().

Replaces custom code with helpers. The pixel-compare helper
pixel_format_equal() also handles indexed color formats. Prepares
for sysfb drivers to support color palettes.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250714151513.309475-4-tzimmermann@suse.de

drm/sysfb: Share helpers for screen_info validation

2025-04-14T08:16:14+00:00

Share efidrm's and vesadrm's validation of struct screen_info in
shared helpers. Update the drivers.

Most validation helpers test individual values against limits and
can be shared as they are. For color formats, a common helper looks
up the correct DRM format info from a driver-provided list of color
formats.

These screen_info helpers are only available if CONFIG_SCREEN_INFO
has been selected, as done by efidrm and vesadrm.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://lore.kernel.org/r/20250410083834.10810-4-tzimmermann@suse.de