Hi Jocelyn, On Mon, Jun 17, 2024 at 10:16 AM Jocelyn Falempe <jfalempe@xxxxxxxxxx> wrote: > On 16/06/2024 14:43, Javier Martinez Canillas wrote: > > Jocelyn Falempe <jfalempe@xxxxxxxxxx> writes: > >> The race condition between fbcon and drm_panic can only occurs if > >> VT_CONSOLE is set. So update drm_panic dependency accordingly. > >> This will make it easier for Linux distributions to enable drm_panic > >> by disabling VT_CONSOLE, and keeping fbcon terminal. > >> The only drawback is that fbcon won't display the boot kmsg, so it > >> should rely on userspace to do that. > >> At least plymouth already handle this case with > >> https://gitlab.freedesktop.org/plymouth/plymouth/-/merge_requests/224 > >> > >> Suggested-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > >> Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx> > >> --- > >> drivers/gpu/drm/Kconfig | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > >> index a9df94291622..f5c989aed7e9 100644 > >> --- a/drivers/gpu/drm/Kconfig > >> +++ b/drivers/gpu/drm/Kconfig > >> @@ -107,7 +107,7 @@ config DRM_KMS_HELPER > >> > >> config DRM_PANIC > >> bool "Display a user-friendly message when a kernel panic occurs" > >> - depends on DRM && !FRAMEBUFFER_CONSOLE > >> + depends on DRM && !(FRAMEBUFFER_CONSOLE && VT_CONSOLE) > > > > I thought the idea was to only make it depend on !VT_CONSOLE, so that > > distros could also enable fbcon / VT but prevent the race condition to > > happen due the VT not being a system console for the kernel to print > > messages ? > > Yes, but when writing the patch, I thought that if you have VT_CONSOLE=y > and FRAMEBUFFER_CONSOLE=n, then there won't be any race condition, and > drm_panic can be enabled safely. > I don't know if that really matters, and if VT_CONSOLE has any usage > apart from fbcon. It is used for any kind of virtual terminal, so also for vgacon. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
