[igt-dev] [v3] tests/kms_color: Fix CRC mismatch issues with ctm test

[Shankar, Uma]

>-----Original Message-----
>From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com]
>Sent: Friday, March 29, 2019 1:09 AM
>To: Shankar, Uma <uma.shankar at intel.com>
>Cc: igt-dev at lists.freedesktop.org; Syrjala, Ville <ville.syrjala at intel.com>; Lankhorst,
>Maarten <maarten.lankhorst at intel.com>
>Subject: Re: [igt-dev] [v3] tests/kms_color: Fix CRC mismatch issues with ctm test
>
>On Wed, Mar 27, 2019 at 01:37:31PM +0000, Shankar, Uma wrote:
>>
>>
>> >-----Original Message-----
>> >From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com]
>> >Sent: Wednesday, March 27, 2019 5:05 PM
>> >To: Shankar, Uma <uma.shankar at intel.com>
>> >Cc: igt-dev at lists.freedesktop.org; Syrjala, Ville
>> ><ville.syrjala at intel.com>; Lankhorst, Maarten
>> ><maarten.lankhorst at intel.com>
>> >Subject: Re: [igt-dev] [v3] tests/kms_color: Fix CRC mismatch issues
>> >with ctm test
>> >
>> >On Wed, Mar 27, 2019 at 10:52:48AM +0000, Shankar, Uma wrote:
>> >>
>> >>
>> >> >On Wed, Mar 27, 2019 at 06:20:10AM +0000, Shankar, Uma wrote:
>> >> >>
>> >> >>
>> >> >> >-----Original Message-----
>> >> >> >From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com]
>> >> >> >Sent: Tuesday, March 26, 2019 10:16 PM
>> >> >> >To: Shankar, Uma <uma.shankar at intel.com>
>> >> >> >Cc: igt-dev at lists.freedesktop.org; Syrjala, Ville
>> >> >> ><ville.syrjala at intel.com>; Lankhorst, Maarten
>> >> >> ><maarten.lankhorst at intel.com>
>> >> >> >Subject: Re: [igt-dev] [v3] tests/kms_color: Fix CRC mismatch
>> >> >> >issues with ctm test
>> >> >> >
>> >> >> >On Tue, Mar 26, 2019 at 10:31:01AM +0000, Shankar, Uma wrote:
>> >> >> >>
>> >> >> >>
>> >> >> >> >-----Original Message-----
>> >> >> >> >From: Shankar, Uma
>> >> >> >> >Sent: Monday, March 25, 2019 2:11 PM
>> >> >> >> >To: igt-dev at lists.freedesktop.org
>> >> >> >> >Cc: Shankar, Uma <uma.shankar at intel.com>
>> >> >> >> >Subject: [v3] tests/kms_color: Fix CRC mismatch issues with
>> >> >> >> >ctm test
>> >> >> >> >
>> >> >> >> >Due to Gamma/Degamma limitation with precision (lack of
>> >> >> >> >exact
>> >> >> >> >1.0
>> >> >> >> >representation) due to ABI restriction, applying linear
>> >> >> >> >gamma affects crc. This patch fixes the same by making ctm
>> >> >> >> >tests independant of
>> >> >> >gamma/degamma.
>> >> >> >> >
>> >> >> >> >v2: Disable degamma/gamma programming for ctm max test as it
>> >> >> >> >leads to crc mimsmatch. Limiting it to this test case alone
>> >> >> >> >as other tests need it to be enabled, hence not touching those scenarios.
>> >> >> >> >
>> >> >> >> >v3: Fixed a fumble with compilation.
>> >> >> >>
>> >> >> >> Hi Ville,
>> >> >> >> Can I keep your RB on this version. We have a clean CI result available
>now.
>> >> >> >
>> >> >> >I'm confused. Why didn't disabling degamma+gamma work?
>> >> >>
>> >> >> We need to disable degamma/gamma and also make sure we don't set
>> >> >> them again with linear values, which was being done currently.
>> >> >> Hence, disabled it and later made sure it's kept at that.
>> >> >
>> >> >Who is turning it back on and why?
>> >>
>> >> When we call disable from IGT, it passes a NULL LUT. In this case,
>> >> default linear LUT is getting applied in kernel. I am not sure if
>> >> we really disable the gamma/degamma fully in driver. It just works
>> >> with linear values
>> >and remains enabled.
>> >
>> >We would disable after
>> >https://patchwork.freedesktop.org/series/58137/
>> >
>> >Hmm. Looks like one patch missing r-b. I should probably go respin
>> >that with Matt's comment added.
>>
>> Ok sure, will re-test the patch once your change is merged and update the test.
>Thanks.
>
>Merged now. Though on GLK the kernel still has to load a linear degamma ramp
>whenever the csc is used since the two are enabled/disabled by the same bit.

Thanks Ville. Will re-try the test and get back.

Regards,
Uma Shankar

>--
>Ville Syrjälä
>Intel