Re: [PATCH] tests/kms_writeback: refresh to expose writeback output

[Abhinav Kumar <quic_abhinavk@quicinc.com>]

On 5/13/2024 3:32 PM, Alex Hung wrote:
> 
> 
> On 2024-05-13 16:20, Abhinav Kumar wrote:
>>
>>
>> On 5/13/2024 3:06 PM, Alex Hung wrote:
>>>
>>>
>>> On 2024-05-13 15:48, Abhinav Kumar wrote:
>>>>
>>>>
>>>> On 5/13/2024 2:30 PM, Alex Hung wrote:
>>>>> With dc2d7fb4f978, all kms_writeback subtests are skipped.
>>>>>
>>>>> Refresh the outputs to grab all supported connectors,
>>>>> the writeback output that is just enabled.
>>>>>
>>>>
>>>> Can you please help to explain how the tests are getting skipped due 
>>>> to setting the client_cap?
>>>>
>>>> And also why calling igt_display_reset_outputs() is fixing this issue?
>>>
>>> Without the igt_display_reset_outputs(), the result is
>>>
>>> IGT-Version: 1.28-gbe9b99928 (x86_64) (Linux: 6.7.0-rc5-99-custom 
>>> x86_64)
>>> Using IGT_SRANDOM=1715637543 for randomisation
>>> Opened device: /dev/dri/card0
>>> Test requirement not met in function __igt_unique____real_main553, 
>>> file ../tests/kms_writeback.c:579:
>>> Test requirement: output
>>> Last errno: 95, Operation not supported
>>> Subtest writeback-pixel-formats: SKIP (0.000s)
>>> Subtest writeback-invalid-parameters: SKIP (0.000s)
>>> Subtest writeback-fb-id: SKIP (0.000s)
>>> Subtest writeback-fb-id-XRGB2101010: SKIP (0.000s)
>>> Subtest writeback-check-output: SKIP (0.000s)
>>> Subtest writeback-check-output-XRGB2101010: SKIP (0.000s)
>>>
>>>
>>> It looks like the below "output = kms_writeback_get_output(&display)" 
>>> will return null as it cannot find any connector type with 
>>> DRM_MODE_CONNECTOR_WRITEBACK.
>>>
>>> The igt_display_reset_outputs() is able to re-initialize the output 
>>> and therefore includes the writeback output.
>>>
>>
>> Thanks for the details, I understand the issue now.
>>
>> But rather than calling igt_display_reset_outputs(), I think better 
>> way will be to set the cap before calling igt_display_require()
>>
>> diff --git a/tests/kms_writeback.c b/tests/kms_writeback.c
>> index f89b2d62fcc9..6ecab46e440b 100644
>> --- a/tests/kms_writeback.c
>> +++ b/tests/kms_writeback.c
>> @@ -567,14 +567,13 @@ igt_main_args("b:c:f:dl", long_options, 
>> help_str, opt_handler, NULL)
>>
>>                  kmstest_set_vt_graphics_mode();
>>
>> +               ret = drmSetClientCap(display.drm_fd, 
>> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS, 1);
>> +               igt_require_f(!ret, "error setting 
>> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS\n");
>> +
>>                  igt_display_require(&display, display.drm_fd);
>>
>> Let me know if that works for you.
>>
> 
> This works if DRM_CLIENT_CAP_ATOMIC is also set as below:
> 
> Is this preferred?
> 
> --- a/tests/kms_writeback.c
> +++ b/tests/kms_writeback.c
> @@ -567,14 +567,18 @@ igt_main_args("b:c:f:dl", long_options, help_str, 
> opt_handler, NULL)
> 
>                  kmstest_set_vt_graphics_mode();
> 
> -               igt_display_require(&display, display.drm_fd);
> -
> -               igt_require(display.is_atomic);
> +               if (drmSetClientCap(display.drm_fd, 
> DRM_CLIENT_CAP_ATOMIC, 1) == 0)
> +                       display.is_atomic = 1;
> 
>                  ret = drmSetClientCap(display.drm_fd, 
> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS, 1);
> 
>                  igt_require_f(!ret, "error setting 
> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS\n");
> 
> +               igt_display_require(&display, display.drm_fd);
> +
> +               igt_require(display.is_atomic);
> +
> +
> 

Yes, looks correct to me because drm driver expects both to be set.

357 	case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
358 		if (!file_priv->atomic)
359 			return -EINVAL;
360 		if (req->value > 1)
361 			return -EINVAL;
362 		file_priv->writeback_connectors = req->value;
363 		break;
> 
> 
> 
>>>>
>>>>> Fixes: dc2d7fb4f978 ("lib/igt_kms: move setting 
>>>>> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS to kms_writeback")
>>>>> Signed-off-by: Alex Hung <alex.hung@amd.com>
>>>>> ---
>>>>>   tests/kms_writeback.c | 4 +++-
>>>>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/tests/kms_writeback.c b/tests/kms_writeback.c
>>>>> index f89b2d62f..4c54f3b89 100644
>>>>> --- a/tests/kms_writeback.c
>>>>> +++ b/tests/kms_writeback.c
>>>>> @@ -572,9 +572,11 @@ igt_main_args("b:c:f:dl", long_options, 
>>>>> help_str, opt_handler, NULL)
>>>>>           igt_require(display.is_atomic);
>>>>>           ret = drmSetClientCap(display.drm_fd, 
>>>>> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS, 1);
>>>>> -
>>>>
>>>> Is this part needed for this patch?
>>>
>>> No, but I think they are related and thus grouping them together is 
>>> easier to read.
>>>
>>>>
>>>>>           igt_require_f(!ret, "error setting 
>>>>> DRM_CLIENT_CAP_WRITEBACK_CONNECTORS\n");
>>>>> +        /* Refresh the outputs to grab all supported connectors.*/
>>>>> +        igt_display_reset_outputs(&display);
>>>>> +
>>>>>           output = kms_writeback_get_output(&display);
>>>>>           igt_require(output);