linux-stable.git/include/linux/fb.h, branch v7.0.4

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

2026-05-07T04:14:00+00:00

commit 9ded47ad003f09a94b6a710b5c47f4aa5ceb7429 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

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

fbdev: Track display blanking state

2025-04-10T09:38:57+00:00

Store the display's blank status in struct fb_info.blank and track
it in fb_blank(). As an extra, the status is now available from the
sysfs blank attribute.

Support for blanking is optional. Therefore framebuffer_alloc()
initializes the state to FB_BLANK_UNBLANK (i.e., the display is
on). If the fb_blank callback has been set, register_framebuffer()
sets the state to FB_BLANK_POWERDOWN. On the first modeset, the
call to fb_blank() will update it to _UNBLANK. This is important,
as listeners to FB_EVENT_BLANK will now see the display being
switched on.

Signed-off-by: Thomas Zimmermann 
Acked-by: Simona Vetter 
Link: https://lore.kernel.org/r/20250321095517.313713-3-tzimmermann@suse.de
Signed-off-by: Lee Jones

fb_defio: do not use deprecated page->mapping, index fields

2025-03-17T05:06:11+00:00

With the introduction of mapping_wrprotect_range() there is no need to use
folio_mkclean() in order to write-protect mappings of frame buffer pages,
and therefore no need to inappropriately set kernel-allocated page->index,
mapping fields to permit this operation.

Instead, store the pointer to the page cache object for the mapped driver
in the fb_deferred_io object, and use the already stored page offset from
the pageref object to look up mappings in order to write-protect them.

This is justified, as for the page objects to store a mapping pointer at
the point of assignment of pages, they must all reference the same
underlying address_space object.  Since the life time of the pagerefs is
also the lifetime of the fb_deferred_io object, storing the pointer here
makes sense.

This eliminates the need for all of the logic around setting and
maintaining page->index,mapping which we remove.

This eliminates the use of folio_mkclean() entirely but otherwise should
have no functional change.

[lorenzo.stoakes@oracle.com: fixup unused variable warnings]
  Link: https://lkml.kernel.org/r/d4018405-2762-4385-a816-e54cc23839ac@lucifer.local
Link: https://lkml.kernel.org/r/81171ab16c14e3df28f6de9d14982cee528d8519.1739029358.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes 
Tested-by: Kajtar Zsolt 
Acked-by: Thomas Zimmermann 
Cc: David Hildenbrand 
Cc: Helge Deller 
Cc: Jaya Kumar 
Cc: Maíra Canal 
Cc: Matthew Wilcox 
Cc: Simona Vetter 
Signed-off-by: Andrew Morton

backlight: lcd: Test against struct fb_info.lcd_dev

2024-09-30T15:49:41+00:00

Add struct fb_info.lcd_dev for fbdev drivers to store a reference to
their lcd device. Update the lcd's fb_notifier_callback() to test for
this field. The lcd module can now detect if an lcd device belongs to
an fbdev device.

This works similar to the bl_dev for backlights and will allow for
the removal of the check_fb callback from several fbdev driver's lcd
devices.

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Daniel Thompson 
Link: https://lore.kernel.org/r/20240906075439.98476-3-tzimmermann@suse.de
Signed-off-by: Lee Jones