Messages in this thread | | | Date | Tue, 18 Oct 2011 10:22:55 +0800 | Subject | Re: [PATCH] drm: avoid switching to text console if there is no panic timeout | From | Dave Young <> |
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On Tue, Oct 18, 2011 at 10:19 AM, Dave Young <hidave.darkstar@gmail.com> wrote: > On Tue, Oct 18, 2011 at 8:06 AM, Mandeep Singh Baines <msb@chromium.org> wrote: >> From: Hugh Dickins <hughd@chromium.org> >> >> Add a check for panic_timeout in the drm_fb_helper_panic() notifier: if >> we're going to reboot immediately, the user will not be able to see the >> messages anyway, and messing with the video mode may display artifacts, >> and certainly get into several layers of complexity (including mutexes and >> memory allocations) which we shall be much safer to avoid. > > There's one exception is use printk_delay
OTOH the complexity do exist also when timeout is set, IMHO it is worth
> >> >> Signed-off-by: Hugh Dickins <hughd@google.com> >> [ Edited commit message and modified to short-circuit panic_timeout < 0 >> instead of testing panic_timeout >= 0. -Mandeep ] >> Signed-off-by: Mandeep Singh Baines <msb@chromium.org> >> Cc: Dave Airlie <airlied@redhat.com> >> Cc: Andrew Morton <akpm@linux-foundation.org> >> Cc: dri-devel@lists.freedesktop.org >> --- >> drivers/gpu/drm/drm_fb_helper.c | 7 +++++++ >> 1 files changed, 7 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c >> index f7c6854..0e62c93 100644 >> --- a/drivers/gpu/drm/drm_fb_helper.c >> +++ b/drivers/gpu/drm/drm_fb_helper.c >> @@ -254,6 +254,13 @@ bool drm_fb_helper_force_kernel_mode(void) >> int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed, >> void *panic_str) >> { >> + /* >> + * It's a waste of time and effort to switch back to text console >> + * if the kernel should reboot before panic messages can be seen. >> + */ >> + if (panic_timeout < 0) >> + return 0; >> + >> printk(KERN_ERR "panic occurred, switching back to text console\n"); >> return drm_fb_helper_force_kernel_mode(); >> } >> -- >> 1.7.3.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ >> > > > > -- > Regards > Dave >
-- Regards Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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