[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: 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.

Regards,
Uma Shankar

>--
>Ville Syrjälä
>Intel