On Thu, 6 Jan 2011 08:29:22 -0800, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Thu, Jan 6, 2011 at 2:48 AM, Michal Hocko <mhocko@xxxxxxx> wrote: > > > > It seems that there is still a regression for intel graphic cards > > backlight. One report is https://bugzilla.kernel.org/show_bug.cgi?id=22672. > > I can reproduce the problem easily by: > > xset dpms force standby; sleep 3s; xset dpms force on > > > > backlight doesn't get up (there is really dark picture though which > > doesn't get brighter by function keys which work normally) after dpms on > > until I close and open lid. > > Hmm. That commit no longer reverts cleanly, so it's not trivial to > test whether all those things are exactly the same issue. It's been > bisected in the bugzilla entry, but it would be good to verify that > yes, reverting it really does fix the issue, and your issue is the > exact same one. > > Chris, any ideas? My fear is that some machines have a dependency between the backlight and panel power status. The patch in question changed the timing between turning on the panel and adjusting the backlight which would be restore with: diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index aa23070..0b40b4f 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -106,6 +106,12 @@ static void intel_lvds_enable(struct intel_lvds *intel_lvds) I915_WRITE(ctl_reg, I915_READ(ctl_reg) | POWER_TARGET_ON); POSTING_READ(lvds_reg); + { + u32 reg = HAS_PCH_SPLIT(dev) ? PCH_PP_STATUS : PPS_STATUS; + if (wait_for(I915_READ(reg) & PP_ON, 1000)) + DRM_ERROR("timed out waiting for panel to power up\n"); + } + intel_panel_set_backlight(dev, dev_priv->backlight_level); } -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
