[0/3] drm/panic: Remove build time dependency with FRAMEBUFFER_CONSOLE

Message

Jocelyn Falempe July 17, 2024, 8:48 a.m. UTC

When proposing to enable DRM_PANIC on Fedora, some users raised concern about the need to disable VT_CONSOLE.
So this is my new attempt to avoid fbcon/vt_console to overwrite the panic screen.
This time it doesn't involve any locking, so it should be safe.
I added a skip_panic option in struct fb_info, and check if this option and the panic_cpu are set in fb_is_inactive(), to prevent any framebuffer operation.
Also skip_panic is only true if the drm driver supports drm_panic, so you will still get the VT panic info on drivers that don't have drm_panic support yet.

Jocelyn Falempe (3):
  drm/panic: Add drm_panic_is_enabled()
  fbcon: Add an option to disable fbcon in panic.
  drm/panic: Remove build time dependency with FRAMEBUFFER_CONSOLE

 drivers/gpu/drm/Kconfig          |  2 +-
 drivers/gpu/drm/drm_fb_helper.c  |  2 ++
 drivers/gpu/drm/drm_panic.c      | 20 ++++++++++++++++++++
 drivers/video/fbdev/core/fbcon.c |  7 ++++++-
 include/drm/drm_panic.h          |  2 ++
 include/linux/fb.h               |  1 +
 6 files changed, 32 insertions(+), 2 deletions(-)


base-commit: a237f217bad50c381773da5b00442710d1449098

Comments

Jocelyn Falempe July 19, 2024, 9:48 a.m. UTC | #1

On 17/07/2024 10:48, Jocelyn Falempe wrote:
> When proposing to enable DRM_PANIC on Fedora, some users raised concern about the need to disable VT_CONSOLE.
> So this is my new attempt to avoid fbcon/vt_console to overwrite the panic screen.
> This time it doesn't involve any locking, so it should be safe.
> I added a skip_panic option in struct fb_info, and check if this option and the panic_cpu are set in fb_is_inactive(), to prevent any framebuffer operation.
> Also skip_panic is only true if the drm driver supports drm_panic, so you will still get the VT panic info on drivers that don't have drm_panic support yet.
> 

Thanks all,

I've just pushed them to drm-misc-next, with the required changes.
(splitting patch 2 in 2, and moving function prototype to 
drm_crtc_internal.h).

Best regards,