linux.git/drivers/video/console/dummycon.c, branch v6.7

console: fix up ARM screen_info reference

2023-10-17T14:34:02+00:00

Separating the VGA console screen_info from the EFI one unfortunately
caused a build failure for footbridge that I had never caught
with randconfig builds:

arch/arm/kernel/setup.c:932:27: error: static declaration of 'vgacon_screen_info' follows non-static declaration
  932 | static struct screen_info vgacon_screen_info = {
      |                           ^~~~~~~~~~~~~~~~~~
In file included from arch/arm/kernel/setup.c:44:
arch/arm/include/asm/setup.h:40:27: note: previous declaration of 'vgacon_screen_info' with type 'struct screen_info'
   40 | extern struct screen_info vgacon_screen_info;
      |                           ^~~~~~~~~~~~~~~~~~
arm-linux-gnueabi-ld: drivers/video/console/dummycon.o: in function `dummycon_init':
dummycon.c:(.text+0xe4): undefined reference to `screen_info'

Make sure the variable is global to avoid the conflict with the extern
declaration, and make it work in dummycon.c

Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20231017093947.3627976-2-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman

dummycon: limit Arm console size hack to footbridge

2023-10-17T08:17:02+00:00

The dummycon default console size used to be determined by architecture,
but now this is a Kconfig setting on everything except ARM. Tracing this
back in the historic git trees, this was used to match the size of VGA
console or VGA framebuffer on early machines, but nowadays that code is
no longer used, except probably on the old footbridge/netwinder since
that is the only one that supports vgacon.

On machines with a framebuffer, booting with DT so far results in always
using the hardcoded 80x30 size in dummycon, while on ATAGS the setting
can come from a bootloader specific override. Both seem to be worse
choices than the Kconfig setting, since the actual text size for fbcon
also depends on the selected font.

Make this work the same way as everywhere else and use the normal
Kconfig setting, except for the footbridge with vgacon, which keeps
using the traditional code. If vgacon is disabled, footbridge can
also ignore the setting. This means the screen_info only has to be
provided when either vgacon or EFI are enabled now.

To limit the amount of surprises on Arm, change the Kconfig default
to the previously used 80x30 setting instead of the usual 80x25.

Reviewed-by: Thomas Zimmermann 
Tested-by: Linus Walleij 
Reviewed-by: Javier Martinez Canillas 
Acked-by: Helge Deller 
Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20231009211845.3136536-4-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman

console: Delete dummy con_font_set() and con_font_default() callback implementations

2020-11-16T15:31:09+00:00

.con_font_set and .con_font_default callbacks should not pass `struct
console_font *` as a parameter, since `struct console_font` is a UAPI
structure.

We are trying to let them use our new kernel font descriptor, `struct
font_desc` instead. To make that work slightly easier, first delete all of
their no-op implementations used by dummy consoles.

This will make KD_FONT_OP_SET and KD_FONT_OP_SET_DEFAULT ioctl() requests
on dummy consoles start to fail and return `-ENOSYS`, which is intended,
since no user should ever expect such operations to succeed on dummy
consoles.

Suggested-by: Daniel Vetter 
Signed-off-by: Peilin Ye 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/9952c7538d2a32bb1a82af323be482e7afb3dedf.1605169912.git.yepeilin.cs@gmail.com

console: Delete unused con_font_copy() callback implementations

2020-11-16T15:27:03+00:00

Recently in commit 3c4e0dff2095 ("vt: Disable KD_FONT_OP_COPY") we
disabled the KD_FONT_OP_COPY ioctl() option. Delete all the
con_font_copy() callbacks, since we no longer use them.

Mark KD_FONT_OP_COPY as "obsolete" in include/uapi/linux/kd.h, just like
what we have done for PPPIOCDETACH in commit af8d3c7c001a ("ppp: remove
the PPPIOCDETACH ioctl").

Signed-off-by: Peilin Ye 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/c8d28007edf50de4387e1532eb3eb736db716f73.1605169912.git.yepeilin.cs@gmail.com

dummycon: Sprinkle locking checks

2019-06-12T18:26:55+00:00

As part of trying to understand the locking (or lack thereof) in the
fbcon/vt/fbdev maze, annotate everything.

Signed-off-by: Daniel Vetter 
Reviewed-by: Sam Ravnborg 
Reviewed-by: Maarten Lankhorst 
Cc: Bartlomiej Zolnierkiewicz 
Cc: Hans de Goede 
Cc: Daniel Vetter 
Cc: Greg Kroah-Hartman 
Cc: Kees Cook 
Cc: Nicolas Pitre 
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-2-daniel.vetter@ffwll.ch

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

dummycon: Stop exporting dummycon_[un]register_output_notifier

2018-08-10T15:23:02+00:00

Now that we only allow FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER when
fbdev+fbcon are builtin exporting these is no longer necessary.

Signed-off-by: Hans de Goede 
Signed-off-by: Bartlomiej Zolnierkiewicz

console: dummycon: export dummycon_[un]register_output_notifier

2018-06-29T09:46:19+00:00

Export dummycon_[un]register_output_notifier, the fbcon code needs this
and may be build as a module.

Fixes: 83d83bebf401 ("console/fbcon: Add support for deferred console takeover")
Cc: Stephen Rothwell 
Reported-by: Stephen Rothwell 
Signed-off-by: Hans de Goede 
Signed-off-by: Bartlomiej Zolnierkiewicz

console/fbcon: Add support for deferred console takeover

2018-06-28T13:20:30+00:00

Currently fbcon claims fbdevs as soon as they are registered and takes over
the console as soon as the first fbdev gets registered.

This behavior is undesirable in cases where a smooth graphical bootup is
desired, in such cases we typically want the contents of the framebuffer
(typically a vendor logo) to stay in place as is.

The current solution for this problem (on embedded systems) is to not
enable fbcon.

This commit adds a new FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER config option,
which when enabled defers fbcon taking over the console from the dummy
console until the first text is displayed on the console. Together with the
"quiet" kernel commandline option, this allows fbcon to still be used
together with a smooth graphical bootup, having it take over the console as
soon as e.g. an error message is logged.

Note the choice to detect the first console output in the dummycon driver,
rather then handling this entirely inside the fbcon code, was made after
2 failed attempts to handle this entirely inside the fbcon code. The fbcon
code is woven quite tightly into the console code, making this to only
feasible option.

Reviewed-by: Daniel Vetter 
Signed-off-by: Hans de Goede 
Signed-off-by: Bartlomiej Zolnierkiewicz

console: Expand dummy functions for CFI

2018-02-27T09:17:33+00:00

This expands the no-op dummy functions into full prototypes to avoid
indirect call mismatches when running under Control Flow Integrity
checking, like with Clang's -fsanitize=cfi.

Co-Developed-by: Sami Tolvanen 
Signed-off-by: Sami Tolvanen 
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman