Re: [igt-dev] [Intel-gfx] [PATCH i-g-t] tests/i915_pm_freq_api: Add a suspend subtest

["Belgaumkar, Vinay" <vinay.belgaumkar@intel.com>]

On 6/7/2023 4:11 PM, Belgaumkar, Vinay wrote:
>
> On 6/7/2023 3:56 PM, Dixit, Ashutosh wrote:
>> On Wed, 07 Jun 2023 15:31:33 -0700, Belgaumkar, Vinay wrote:
>>> On 6/7/2023 2:12 PM, Dixit, Ashutosh wrote:
>>>> On Tue, 06 Jun 2023 13:35:35 -0700, Vinay Belgaumkar wrote:
>>>> Hi Vinay,
>>>>
>>>>> Verify that SLPC API works as expected after a suspend.
>>>>>
>>>>> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
>>>>> ---
>>>>>    tests/i915/i915_pm_freq_api.c | 30 ++++++++++++++++++++++++++++++
>>>>>    1 file changed, 30 insertions(+)
>>>>>
>>>>> diff --git a/tests/i915/i915_pm_freq_api.c 
>>>>> b/tests/i915/i915_pm_freq_api.c
>>>>> index 9005cd220..f35f1f8e0 100644
>>>>> --- a/tests/i915/i915_pm_freq_api.c
>>>>> +++ b/tests/i915/i915_pm_freq_api.c
>>>>> @@ -18,6 +18,9 @@
>>>>>     *
>>>>>     * SUBTEST: freq-reset
>>>>>     * Description: Test basic freq API works after a reset
>>>>> + *
>>>>> + * SUBTEST: freq-suspend
>>>>> + * Description: Test basic freq API works after a runtime suspend
>>>>>     */
>>>>>
>>>>>    IGT_TEST_DESCRIPTION("Test SLPC freq API");
>>>>> @@ -99,6 +102,24 @@ static void test_reset(int i915, int dirfd, 
>>>>> int gt)
>>>>>     igt_assert(get_freq(dirfd, RPS_MAX_FREQ_MHZ) == rpn);
>>>>>    }
>>>>>
>>>>> +static void test_suspend(int i915, int dirfd, int gt)
>>>>> +{
>>>>> +    uint32_t rpn = get_freq(dirfd, RPS_RPn_FREQ_MHZ);
>>>>> +
>>>>> +    igt_assert(set_freq(dirfd, RPS_MIN_FREQ_MHZ, rpn) > 0);
>>>>> +    igt_assert(set_freq(dirfd, RPS_MAX_FREQ_MHZ, rpn) > 0);
>>>>> +    usleep(ACT_FREQ_LATENCY_US);
>>>>> +    igt_assert(get_freq(dirfd, RPS_MIN_FREQ_MHZ) == rpn);
>>>>> +    igt_assert(get_freq(dirfd, RPS_MAX_FREQ_MHZ) == rpn);
>>>>> +
>>>>> +    /* Manually trigger a suspend */
>>>>> +    igt_system_suspend_autoresume(SUSPEND_STATE_S3,
>>>>> +                      SUSPEND_TEST_NONE);
>>>>> +
>>>>> +    igt_assert(get_freq(dirfd, RPS_MIN_FREQ_MHZ) == rpn);
>>>>> +    igt_assert(get_freq(dirfd, RPS_MAX_FREQ_MHZ) == rpn);
>>>> I am wondering what the purpose/value of this test (and also 
>>>> "freq-reset")
>>>> is?  How can the "set" min/max set freq (which are just input 
>>>> settings)
>>>> change whether or not there is a suspend/resume or a reset? 
>>>> Especially when
>>>> we just return cached min/max values from i915?
>>> It is mainly checking that we don't smother the softlimit during a 
>>> reset or
>>> suspend flow.
>> How can softlimit which is a ordinary variable in memory get 
>> clobbered by
>> suspend resume?

It shouldn't, but funnier things have happened. Anyways, I can add a 
check for cur_freq and ensure that is at min. That will prove we applied 
the soft limit after suspend.

Thanks,

Vinay.

>>
>>> In addition, it also tests the read/write interface works as expected
>>> after those events.
>> There's no write. Sorry, but I'm not convinced. There should be some 
>> more
>> meat to the test.
> There are writes in the IGT fixture after the test completes.
>>
>> Maybe we can write a test which will check /all/ sysfs values are the 
>> same
>> after a suspend resume cycle? Why do only these specific ones have to be
>> checked?
>
> This test is specific to the freq api, hence just min/max entries.
>
> Thanks,
>
> Vinay.
>
>>
>> Thanks.
>> -- 
>> Ashutosh
>>
>>
>>> Thanks,
>>>
>>> Vinay.
>>>
>>>> Thanks.
>>>> -- 
>>>> Ashutosh
>>>>
>>>>
>>>>> +}
>>>>> +
>>>>>    igt_main
>>>>>    {
>>>>>     int i915 = -1;
>>>>> @@ -143,6 +164,15 @@ igt_main
>>>>>                 test_reset(i915, dirfd, gt);
>>>>>     }
>>>>>
>>>>> +    igt_describe("Test basic freq API works after suspend");
>>>>> +    igt_subtest_with_dynamic_f("freq-suspend") {
>>>>> +        int dirfd, gt;
>>>>> +
>>>>> +        for_each_sysfs_gt_dirfd(i915, dirfd, gt)
>>>>> +            igt_dynamic_f("gt%u", gt)
>>>>> +                test_suspend(i915, dirfd, gt);
>>>>> +    }
>>>>> +
>>>>>     igt_fixture {
>>>>>         int dirfd, gt;
>>>>>         /* Restore frequencies */
>>>>> -- 
>>>>> 2.38.1
>>>>>