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

[Paulo Zanoni]

2014-02-06 15:22 GMT-02:00 Chris Wilson <chris at chris-wilson.co.uk>:
> 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.

Oh, well, at least we didn't break suspend/resume :)

I just requested some information at the bugzilla entry created by
Chris. Can you please provide the requested files there, and move the
discussion to bugzilla?

>
> I've filed this as https://bugs.freedesktop.org/show_bug.cgi?id=74628

Thanks for doing this! It's too easy to forget about mailing-list-only
bug reports.

> Thanks,
> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
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-- 
Paulo Zanoni