fbdev/core: Rework fb init code

Init the class "graphics" before the rest of fbdev. Later steps, such
as the sysfs code, depend on the class. Also arrange the module's exit
code in reverse order.

U

fbdev/core: Rework fb init code

Init the class "graphics" before the rest of fbdev. Later steps, such
as the sysfs code, depend on the class. Also arrange the module's exit
code in reverse order.

Unexport the global variable fb_class, which is only shared internally
within the fbdev core module.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-38-tzimmermann@suse.de

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fbdev/core: Move file-I/O code into separate file

Move fbdev's file-I/O code into a separate file and contain it in
init and cleanup helpers. No functional changes.

v3:
* add missing file fb_chrde

fbdev/core: Move file-I/O code into separate file

Move fbdev's file-I/O code into a separate file and contain it in
init and cleanup helpers. No functional changes.

v3:
* add missing file fb_chrdev.c
v2:
* rename source file (Sam)
* include <linux/compat.h> (Javier, kernel test robot)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-37-tzimmermann@suse.de

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fbdev/core: Move procfs code to separate file

Move fbdev's procfs code into a separate file and contain it in
init and cleanup helpers. For the cleanup, replace remove_proc_entry()
with proc_remove(

fbdev/core: Move procfs code to separate file

Move fbdev's procfs code into a separate file and contain it in
init and cleanup helpers. For the cleanup, replace remove_proc_entry()
with proc_remove(). It is equivalent in functionality, but looks
more like an inverse of proc_create_seq().

v2:
* document proc_remove() usage (Sam)
* revert unrelated removal of for_each_registered_fb()

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-36-tzimmermann@suse.de

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fbdev/core: Add fb_device_{create,destroy}()

Move the logic to create and destroy fbdev devices into the new
helpers fb_device_create() and fb_device_destroy().

There was a call to fb_cleanup_devic

fbdev/core: Add fb_device_{create,destroy}()

Move the logic to create and destroy fbdev devices into the new
helpers fb_device_create() and fb_device_destroy().

There was a call to fb_cleanup_device() in do_unregister_framebuffer()
that was too late. The device had already been removed at this point.
Move the call into fb_device_destroy().

Declare the helpers in the new internal header file fb_internal.h, as
they are only used within the fbdev core module.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-35-tzimmermann@suse.de

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fbdev/core: Pass Linux device to pm_vt_switch_*() functions

Pass the Linux device to pm_vt_switch_*() instead of the virtual
fbdev device. Prepares fbdev for making struct fb_info.dev optional.

The

fbdev/core: Pass Linux device to pm_vt_switch_*() functions

Pass the Linux device to pm_vt_switch_*() instead of the virtual
fbdev device. Prepares fbdev for making struct fb_info.dev optional.

The type of device that is passed to the PM functions does not matter
much. It is only a token within the internal list of known devices.
The PM functions do not refer to any of the device's properties or its
type.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-pm@vger.kernel.org
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-33-tzimmermann@suse.de

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fbdev: fbmem: mark get_fb_unmapped_area() static

There is a global function with this name on sparc, but no
global declaration:

drivers/video/fbdev/core/fbmem.c:1469:15: error: no previous prototyp

fbdev: fbmem: mark get_fb_unmapped_area() static

There is a global function with this name on sparc, but no
global declaration:

drivers/video/fbdev/core/fbmem.c:1469:15: error: no previous prototype for 'get_fb_unmapped_area'

Make the generic definition static to avoid this warning. On
sparc, this is never seen.

Edit by Helge:
Update Kconfig text as suggested by Geert Uytterhoeven.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Helge Deller <deller@gmx.de>

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fbdev: Include <linux/fb.h> instead of <asm/fb.h>

Replace include statements for <asm/fb.h> with <linux/fb.h>. Fixes
the coding style: if a header is available in asm/ and linux/, it
is preferable t

fbdev: Include <linux/fb.h> instead of <asm/fb.h>

Replace include statements for <asm/fb.h> with <linux/fb.h>. Fixes
the coding style: if a header is available in asm/ and linux/, it
is preferable to include the header from linux/. This only affects
a few source files, most of which already include <linux/fb.h>.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230512102444.5438-6-tzimmermann@suse.de

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fbdev: Move I/O read and write code into helper functions

Move the existing I/O read and write code for I/O memory into
the new helpers fb_cfb_read() and fb_cfb_write(). Make them the
default fp_ops

fbdev: Move I/O read and write code into helper functions

Move the existing I/O read and write code for I/O memory into
the new helpers fb_cfb_read() and fb_cfb_write(). Make them the
default fp_ops. No functional changes.

In the near term, the new functions will be useful to the DRM
subsystem, which currently provides it's own implementation. It
can then use the shared code. In the longer term, it might make
sense to revise the I/O helper's default status and make them
opt-in by the driver. Systems that don't use them would not
contain the code any longer.

v2:
* add detailed commit message (Javier)
* rename fb_cfb_() to fb_io_() (Geert)
* add fixes that got lost while moving the code (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-19-tzimmermann@suse.de

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fbdev: Validate info->screen_{base, buffer} in fb_ops implementations

Push the test for info->screen_base from fb_read() and fb_write() into
the implementations of struct fb_ops.{fb_read,fb_write}.

fbdev: Validate info->screen_{base, buffer} in fb_ops implementations

Push the test for info->screen_base from fb_read() and fb_write() into
the implementations of struct fb_ops.{fb_read,fb_write}. In cases where
the driver operates on info->screen_buffer, test this field instead.

While bothi fields, screen_base and screen_buffer, are stored in the
same location, they refer to different address spaces. For correctness,
we want to test each field in exactly the code that uses it.

v2:
* also test screen_base in pvr2fb (Geert)
* also test screen_buffer in ivtvfb, arcfb, broadsheetfb,
hecubafb, metronomefb and ssd1307fb (Geert)
* give a rational for the change (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-18-tzimmermann@suse.de

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fbdev: Return number of bytes read or written

Always return the number of bytes read or written within the
framebuffer. Only return an errno code if framebuffer memory
was not touched. This is the s

fbdev: Return number of bytes read or written

Always return the number of bytes read or written within the
framebuffer. Only return an errno code if framebuffer memory
was not touched. This is the semantics required by POSIX and
makes fb_read() and fb_write() compatible with IGT tests. [1]

This bug has been fixed for fb_write() long ago by
commit 6a2a88668e90 ("[PATCH] fbdev: Fix return error of
fb_write"). The code in fb_read() and the corresponding fb_sys_()
helpers was forgotten.

It can happen that copy_{from, to}_user() only partially copies
the given buffer. Take this into account when calculating the
number of bytes.

v2:
* consider return value from copy_{from,to}_user() (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Helge Deller <deller@gmx.de>
Link: https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/tests/fbdev.c # 1
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-15-tzimmermann@suse.de

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fbmem: Reject FB_ACTIVATE_KD_TEXT from userspace

This is an oversight from dc5bdb68b5b3 ("drm/fb-helper: Fix vt
restore") - I failed to realize that nasty userspace could set this.

It's not pretty

fbmem: Reject FB_ACTIVATE_KD_TEXT from userspace

This is an oversight from dc5bdb68b5b3 ("drm/fb-helper: Fix vt
restore") - I failed to realize that nasty userspace could set this.

It's not pretty to mix up kernel-internal and userspace uapi flags
like this, but since the entire fb_var_screeninfo structure is uapi
we'd need to either add a new parameter to the ->fb_set_par callback
and fb_set_par() function, which has a _lot_ of users. Or some other
fairly ugly side-channel int fb_info. Neither is a pretty prospect.

Instead just correct the issue at hand by filtering out this
kernel-internal flag in the ioctl handling code.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Fixes: dc5bdb68b5b3 ("drm/fb-helper: Fix vt restore")
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: shlomo@fastmail.com
Cc: Michel Dänzer <michel@daenzer.net>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.7+
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Qiujun Huang <hqjagain@gmail.com>
Cc: Peter Rosin <peda@axentia.se>
Cc: linux-fbdev@vger.kernel.org
Cc: Helge Deller <deller@gmx.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Shigeru Yoshida <syoshida@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230404193934.472457-1-daniel.vetter@ffwll.ch

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driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
s

driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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fbdev: Fix invalid page access after closing deferred I/O devices

When a fbdev with deferred I/O is once opened and closed, the dirty
pages still remain queued in the pageref list, and eventually la

fbdev: Fix invalid page access after closing deferred I/O devices

When a fbdev with deferred I/O is once opened and closed, the dirty
pages still remain queued in the pageref list, and eventually later
those may be processed in the delayed work. This may lead to a
corruption of pages, hitting an Oops.

This patch makes sure to cancel the delayed work and clean up the
pageref list at closing the device for addressing the bug. A part of
the cleanup code is factored out as a new helper function that is
called from the common fb_release().

Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Miko Larsson <mikoxyzzz@gmail.com>
Fixes: 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct")
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230129082856.22113-1-tiwai@suse.de

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drm/fbdev: Remove aperture handling and FBINFO_MISC_FIRMWARE

There are no users left of struct fb_info.apertures and the flag
FBINFO_MISC_FIRMWARE. Remove both and the aperture-ownership code
in the

drm/fbdev: Remove aperture handling and FBINFO_MISC_FIRMWARE

There are no users left of struct fb_info.apertures and the flag
FBINFO_MISC_FIRMWARE. Remove both and the aperture-ownership code
in the fbdev core. All code for aperture ownership is now located
in the fbdev drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219160516.23436-19-tzimmermann@suse.de

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fbdev: Add support for the nomodeset kernel parameter

Support the kernel's nomodeset parameter for all PCI-based fbdev
drivers that use aperture helpers to remove other, hardware-agnostic
graphics d

fbdev: Add support for the nomodeset kernel parameter

Support the kernel's nomodeset parameter for all PCI-based fbdev
drivers that use aperture helpers to remove other, hardware-agnostic
graphics drivers.

The parameter is a simple way of using the firmware-provided scanout
buffer if the hardware's native driver is broken. The same effect
could be achieved with per-driver options, but the importance of the
graphics output for many users makes a single, unified approach
worthwhile.

With nomodeset specified, the fbdev driver module will not load. This
unifies behavior with similar DRM drivers. In DRM helpers, modules
first check the nomodeset parameter before registering the PCI
driver. As fbdev has no such module helpers, we have to modify each
driver individually.

The name 'nomodeset' is slightly misleading, but has been chosen for
historical reasons. Several drivers implemented it before it became a
general option for DRM. So keeping the existing name was preferred over
introducing a new one.

v2:
* print a warning if a driver does not init (Helge)
* wrap video_firmware_drivers_only() in helper

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221111133024.9897-3-tzimmermann@suse.de

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fbdev: Make registered_fb[] private to fbmem.c

No driver access this anymore, except for the olpc dcon fbdev driver but
that has been marked as broken anyways by commit de0952f267ff ("staging:
olpc_

fbdev: Make registered_fb[] private to fbmem.c

No driver access this anymore, except for the olpc dcon fbdev driver but
that has been marked as broken anyways by commit de0952f267ff ("staging:
olpc_dcon: mark driver as broken").

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220725075400.68478-1-javierm@redhat.com

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fbdev: Remove conflict-handling code

Remove the call to do_remove_conflicting_framebuffers() from the
framebuffer registration. Aperture helpers take care of removing
conflicting devices. With all o

fbdev: Remove conflict-handling code

Remove the call to do_remove_conflicting_framebuffers() from the
framebuffer registration. Aperture helpers take care of removing
conflicting devices. With all ownership information stored in the
aperture datastrcutures, remove remove_conflicting_framebuffers()
entirely.

This change also rectifies DRM generic-framebuffer registration, which
tried to unregister conflicting framebuffers, even though it's entirely
build on top of DRM.

v2:
* remove internal aperture-overlap helpers, which are
now unused

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220718072322.8927-12-tzimmermann@suse.de

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fbdev: Acquire framebuffer apertures for firmware devices

When registering a generic framebuffer, automatically acquire ownership
of the framebuffer's I/O range. The device will now be handled by th

fbdev: Acquire framebuffer apertures for firmware devices

When registering a generic framebuffer, automatically acquire ownership
of the framebuffer's I/O range. The device will now be handled by the
aperture helpers. Fbdev-based conflict handling is no longer required.

v2:
* use fb_ prefix instead of fbm_ (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220718072322.8927-11-tzimmermann@suse.de

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video: Provide constants for VGA I/O range

Provide VGA_FB_ constants for the VGA framebuffer I/O range and convert
fbdev code. In the case of vga16fb, this is a rename of the existing
constants VGA_

video: Provide constants for VGA I/O range

Provide VGA_FB_ constants for the VGA framebuffer I/O range and convert
fbdev code. In the case of vga16fb, this is a rename of the existing
constants VGA_FB_PHYS and VGA_FB_PHYS_LEN.

v2:
* clarify relationship with old constants in vga16fb (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220718072322.8927-9-tzimmermann@suse.de

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video/aperture: Disable and unregister sysfb devices via aperture helpers

Call sysfb_disable() before removing conflicting devices in aperture
helpers. Fixes sysfb state if fbdev has been disabled.

video/aperture: Disable and unregister sysfb devices via aperture helpers

Call sysfb_disable() before removing conflicting devices in aperture
helpers. Fixes sysfb state if fbdev has been disabled.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Fixes: fb84efa28a48 ("drm/aperture: Run fbdev removal before internal helpers")
Cc: Zack Rusin <zackr@vmware.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Changcheng Deng <deng.changcheng@zte.com.cn>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: dri-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20220718072322.8927-8-tzimmermann@suse.de

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fbdev/core: Remove remove_conflicting_pci_framebuffers()

Remove remove_conflicting_pci_framebuffers() and implement similar
functionality in aperture_remove_conflicting_pci_device(), which was
the o

fbdev/core: Remove remove_conflicting_pci_framebuffers()

Remove remove_conflicting_pci_framebuffers() and implement similar
functionality in aperture_remove_conflicting_pci_device(), which was
the only caller. Removes an otherwise unused interface and streamlines
the aperture helper. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220718072322.8927-5-tzimmermann@suse.de

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fbmem: Check virtual screen sizes in fb_set_var()

Verify that the fbdev or drm driver correctly adjusted the virtual
screen sizes. On failure report the failing driver and reject the screen
size cha

fbmem: Check virtual screen sizes in fb_set_var()

Verify that the fbdev or drm driver correctly adjusted the virtual
screen sizes. On failure report the failing driver and reject the screen
size change.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+

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fbcon: Prevent that screen size is smaller than font size

We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on t

fbcon: Prevent that screen size is smaller than font size

We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.

This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary. The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+

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fbdev: fbmem: Fix logo center image dx issue

Image.dx gets wrong value because of missing '()'.

If xres == logo->width and n == 1, image.dx = -16.

Signed-off-by: Guiling Deng <greens9@163.com>
Fix

fbdev: fbmem: Fix logo center image dx issue

Image.dx gets wrong value because of missing '()'.

If xres == logo->width and n == 1, image.dx = -16.

Signed-off-by: Guiling Deng <greens9@163.com>
Fixes: 3d8b1933eb1c ("fbdev: fbmem: add config option to center the bootup logo")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Helge Deller <deller@gmx.de>

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fbdev: Disable sysfb device registration when removing conflicting FBs

The platform devices registered by sysfb match with firmware-based DRM or
fbdev drivers, that are used to have early graphics u

fbdev: Disable sysfb device registration when removing conflicting FBs

The platform devices registered by sysfb match with firmware-based DRM or
fbdev drivers, that are used to have early graphics using a framebuffer
provided by the system firmware.

DRM or fbdev drivers later are probed and remove conflicting framebuffers,
leading to these platform devices for generic drivers to be unregistered.

But the current solution has a race, since the sysfb_init() function could
be called after a DRM or fbdev driver is probed and request to unregister
the devices for drivers with conflicting framebuffes.

To prevent this, disable any future sysfb platform device registration by
calling sysfb_disable(), if a driver requests to remove the conflicting
framebuffers.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220607182338.344270-4-javierm@redhat.com

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