On Sun, Jan 27, 2013 at 12:42 PM, Daniel Vetter <daniel.vetter@xxxxxxxx> wrote: > Otherwise the system will burn even brighter and worse, leave the user > wondering what's going on exactly. > > Since we already have a panic handler which will (try) to restore the > entire fbdev console mode, we can just bail out. Inspired by a patch > from Konstantin Khlebnikov. The callchain leading to this, cut&pasted > from Konstantin's original patch: > > callstack: > panic() > bust_spinlocks(1) > unblank_screen() > vc->vc_sw->con_blank() > fbcon_blank() > fb_blank() > info->fbops->fb_blank() > drm_fb_helper_blank() > drm_fb_helper_dpms() > drm_modeset_lock_all() > mutex_lock(&dev->mode_config.mutex) > > Note that the entire locking in the fb helper around panic/sysrq and > kdbg is ... non-existant. So we have a decent change of blowing up > everything. But since reworking this ties in with funny concepts like > the fbdev notifier chain or the impressive things which happen around > console_lock while oopsing, I'll leave that as an exercise for braver > souls than me. > > v2: Drop the -EBUSY return value I've copied, we don't need it since > the we'll take care of things ourselves anyway. > > Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > References: https://patchwork.kernel.org/patch/1878181/ > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Reviewed-by: Rob Clark <robdclark@xxxxxxxxx> > --- > drivers/gpu/drm/drm_fb_helper.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c > index a7538cc..01099b5 100644 > --- a/drivers/gpu/drm/drm_fb_helper.c > +++ b/drivers/gpu/drm/drm_fb_helper.c > @@ -386,6 +386,14 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode) > int i, j; > > /* > + * fbdev->blank can be called from irq context in case of a panic. > + * Since we already have our own special panic handler which will > + * restore the fbdev console mode completely, just bail out early. > + */ > + if (oops_in_progress) > + return; > + > + /* > * For each CRTC in this fb, turn the connectors on/off. > */ > drm_modeset_lock_all(dev); > -- > 1.7.10.4 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
