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

[Patrik Jakobsson]

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.

Thanks
Patrik Jakobsson