[Intel-gfx] [PATCH 3/5] drm/i915: fix VDD override off wait

[Chris Wilson]

On Thu, Feb 06, 2014 at 06:16:02PM +0100, Patrik Jakobsson wrote:
> On Fri, Dec 6, 2013 at 8:47 PM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> > On Fri,  6 Dec 2013 17:32:42 -0200
> > Paulo Zanoni <przanoni at gmail.com> wrote:
> >
> >> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >>
> >> If we're disabling the VDD override bit and the panel is enabled, we
> >> don't need to wait for anything. If the panel is disabled, then we
> >> need to actually wait for panel_power_cycle_delay, not
> >> panel_power_down_delay, because the power down delay was already
> >> respected when we disabled the panel.
> >>
> >> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/intel_dp.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >> index fe327ce..a2aace2 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp.c
> >> @@ -1142,7 +1142,9 @@ static void ironlake_panel_vdd_off_sync(struct intel_dp *intel_dp)
> >>               /* Make sure sequencer is idle before allowing subsequent activity */
> >>               DRM_DEBUG_KMS("PP_STATUS: 0x%08x PP_CONTROL: 0x%08x\n",
> >>               I915_READ(pp_stat_reg), I915_READ(pp_ctrl_reg));
> >> -             msleep(intel_dp->panel_power_down_delay);
> >> +
> >> +             if ((pp & POWER_TARGET_ON) == 0)
> >> +                     msleep(intel_dp->panel_power_cycle_delay);
> >>       }
> >>  }
> >>
> >
> > Lemme check the eDP docs on this one...  it's supposed to be T12, which
> > is the time between power cycles.  Yeah that matches what we're using
> > elsewhere, so:
> >
> > Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> 
> Starting with this patch I get a blank screen when booting my MacBook Air 6,2.
> Reverting only this patch on top of 3.14-rc1 doesn't help so it's most likely
> the entire series that needs to be looked at.
> 
> Doing a suspend/resume fixes the problem.

I've filed this as https://bugs.freedesktop.org/show_bug.cgi?id=74628
Thanks,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre