[Intel-gfx] [PATCH 28/31] drm/i915: Make Sink crc calculation waiting for counter to reset.

[Paulo Zanoni]

2015-11-10 18:31 GMT-02:00 Paulo Zanoni <przanoni at gmail.com>:
> 2015-11-05 16:50 GMT-02:00 Rodrigo Vivi <rodrigo.vivi at intel.com>:
>> According to VESA DP spec TEST_CRC_COUNT (Bits 3:0) at
>> TEST_SINK_MISC (00246h) is "Reset to 0 when TEST_SINK bit 0 = 0;
>>
>> So let's give few vblanks so we are really sure that this counter
>> is really zeroed on the next sink_crc read.
>>
>> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 19 ++++++++++++++++++-
>>  1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index c0fa90a..5d810cd 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -3806,6 +3806,8 @@ static int intel_dp_sink_crc_stop(struct intel_dp *intel_dp)
>>         struct intel_crtc *intel_crtc = to_intel_crtc(dig_port->base.base.crtc);
>>         u8 buf;
>>         int ret = 0;
>> +       int count = 0;
>> +       int attempts = 10;
>>
>>         if (drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf) < 0) {
>>                 DRM_DEBUG_KMS("Sink CRC couldn't be stopped properly\n");
>> @@ -3820,7 +3822,22 @@ static int intel_dp_sink_crc_stop(struct intel_dp *intel_dp)
>>                 goto out;
>>         }
>>
>> -       intel_wait_for_vblank(dev, intel_crtc->pipe);
>> +       do {
>> +               intel_wait_for_vblank(dev, intel_crtc->pipe);
>> +
>> +               if (drm_dp_dpcd_readb(&intel_dp->aux,
>> +                                     DP_TEST_SINK_MISC, &buf) < 0) {
>> +                       ret = -EIO;
>> +                       goto out;
>
> This "goto out" will make sink_crc.started remain as true even though
> we already sent the DPCD message telling it to stop, and it
> acknowledged our message. And it won't even print stuff on dmesg. I
> guess I'd probably write something on dmesg and flip started to false.

Now I see that patch 30 deals with this issue.

>
>> +               }
>> +               count = buf & DP_TEST_COUNT_MASK;
>> +       } while (--attempts && count);
>> +
>> +       if (attempts == 0) {
>> +               DRM_ERROR("TIMEOUT: Sink CRC counter is not zeroed\n");
>
> The other errors are all DRM_DEBUG_KMS. On one hand we can't do
> anything about them since they're most likely panel errors so
> DRM_ERROR doesn't look good. On the other hand normal users are not
> going to ever run this code, and DRM_ERROR may make us - and our
> testing robots - notice the possible failures, so maybe DRM_ERROR is
> the way to go here. Anyway, we should be consistent regardless of the
> decision.
>
> Besides, at intel_dp_sink_crc_start(), we read the last_count, but
> it's supposed to be zero. Can't we use a check for this there too?
> Maybe just an informative DRM_DEBUG_KMS("this was supposed to be zero
> but it's not\n") without really returning.

This is addressed by patch 29.

>
> Everything else looks good.

So with or without the changes between the log level of the messages
(since end users shouldn't be running them):
Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

I also vote that we merge 27, 28, 29 and 30 right now since they don't
require patches 1-26. The only conflict is the rename of the IPS
functions, and this can be easily fixed in the patch file.

>
>> +               ret = -ETIMEDOUT;
>> +       }
>> +
>>         intel_dp->sink_crc.started = false;
>>   out:
>>         intel_ips_enable(intel_crtc);
>> --
>> 2.4.3
>>
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>
>
>
> --
> Paulo Zanoni



-- 
Paulo Zanoni