linux.git/include/linux/fb.h, branch v7.1-rc2

fbdev: Declare src parameter of fb_pad_ helpers as constant

2026-03-09T14:47:20+00:00

Fbdev's padding helpers do not modify the source buffer. Declare the
parameter as 'const'.

Fbcon's font-rendering code calls these helpers with the font data.
Declaring src as const will allow for making the font data constant
as well.

While at it, also remove the extern qualifier from the function
declarations in the header file.

Signed-off-by: Thomas Zimmermann 
Signed-off-by: Helge Deller

fbdev: defio: Move pageref array to struct fb_deferred_io_state

2026-03-09T12:06:48+00:00

The pageref array stores all pageref structures for a device's defio
helpers. Move it into struct fb_deferred_io_state to not expose it to
drivers.

Signed-off-by: Thomas Zimmermann 
Signed-off-by: Helge Deller

fbdev: defio: Move variable state into struct fb_deferred_io_state

2026-03-09T12:06:48+00:00

Move variable fields from struct fb_deferred_io into struct
fb_deferred_io_state. These fields are internal to the defio code
and should not be exposed to drivers. At some later point, struct
fb_defered_io might become const in all defio code.

Signed-off-by: Thomas Zimmermann 
Signed-off-by: Helge Deller

fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info

2026-03-09T12:06:48+00:00

Hold state of deferred I/O in struct fb_deferred_io_state. Allocate an
instance as part of initializing deferred I/O and remove it only after
the final mapping has been closed. If the fb_info and the contained
deferred I/O meanwhile goes away, clear struct fb_deferred_io_state.info
to invalidate the mapping. Any access will then result in a SIGBUS
signal.

Fixes a long-standing problem, where a device hot-unplug happens while
user space still has an active mapping of the graphics memory. The hot-
unplug frees the instance of struct fb_info. Accessing the memory will
operate on undefined state.

Signed-off-by: Thomas Zimmermann 
Fixes: 60b59beafba8 ("fbdev: mm: Deferred IO support")
Cc: Helge Deller 
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # v2.6.22+
Signed-off-by: Helge Deller

fbcon: Declare struct fb_info.fbcon_par as of type struct fbcon_par

2026-02-14T10:09:47+00:00

The only correct type for the field fbcon_par in struct fb_info
is struct fbcon_par. Declare is as such. The field is a pointer
to fbcon-private data.

Signed-off-by: Thomas Zimmermann 
Signed-off-by: Helge Deller

fb: Add dev_of_fbinfo() helper for optional sysfs support

2026-02-14T10:09:45+00:00

Add dev_of_fbinfo() to return the framebuffer struct device when
CONFIG_FB_DEVICE is enabled, or NULL otherwise.

This allows fbdev drivers to use sysfs interfaces via runtime checks
instead of CONFIG_FB_DEVICE ifdefs, keeping the code clean while
remaining fully buildable.

Suggested-by: Helge Deller 
Reviewed-by: Helge Deller 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Chintan Patel 
Reviewed-by: Thomas Zimmermann 
Signed-off-by: Helge Deller

fbdev: Use device_create_with_groups() to fix sysfs groups registration race

2026-02-14T10:07:12+00:00

The fbdev sysfs attributes are registered after sending the uevent for
the device creation, leaving a race window where e.g. udev rules may
not be able to access the sysfs attributes because the registration is
not done yet.

Fix this by switching to device_create_with_groups(). This also results in
a nice cleanup. After switching to device_create_with_groups() all that
is left of fb_init_device() is setting the drvdata and that can be passed
to device_create[_with_groups]() too. After which fb_init_device() can
be completely removed.

Dropping fb_init_device() + fb_cleanup_device() in turn allows removing
fb_info.class_flag as they were the only user of this field.

Fixes: 5fc830d6aca1 ("fbdev: Register sysfs groups through device_add_group")
Cc: stable@vger.kernel.org
Cc: Shixiong Ou 
Signed-off-by: Hans de Goede 
Signed-off-by: Helge Deller

fbcon: Remove fb_debug_enter/_leave from struct fb_ops

2025-12-02T08:20:44+00:00

There are no implementations of fb_debug_enter and fb_debug_leave.
Remove the callbacks from struct fb_ops and clean up the caller.

The field save_graphics in fbcon_par is also no longer required.
Remove it as well.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Simona Vetter 
Acked-by: Daniel Thompson (RISCstar) 
Link: https://patch.msgid.link/20251125130634.1080966-6-tzimmermann@suse.de

fbdev: Remove constants of unused events

2025-04-10T09:39:14+00:00

The constants FB_EVENT_MODE_CHANGE and FB_EVENT_BLANK are unused.
Remove them from the header file.

Signed-off-by: Thomas Zimmermann 
Acked-by: Simona Vetter 
Link: https://lore.kernel.org/r/20250321095517.313713-12-tzimmermann@suse.de
Signed-off-by: Lee Jones

backlight: Replace fb events with a dedicated function call

2025-04-10T09:39:03+00:00

Remove support for fb events from backlight subsystem. Provide the
helper backlight_notify_blank_all() instead. Also export the existing
helper backlight_notify_blank() to update a single backlight device.

In fbdev, call either helper to inform the backlight subsystem of
changes to a display's blank state. If the framebuffer device has a
specific backlight, only update this one; otherwise update all.

v4:
- protect blacklight declarations with IS_REACHABLE() (kernel test robot)
v3:
- declare empty fb_bl_notify_blank() as static inline (kernel test robot)

Signed-off-by: Thomas Zimmermann 
Acked-by: Simona Vetter 
Reviewed-by: "Daniel Thompson (RISCstar)" 
Link: https://lore.kernel.org/r/20250321095517.313713-7-tzimmermann@suse.de
Signed-off-by: Lee Jones