Re: [igt-dev] [RFC PATCH 1/2] tests/kms_vrr: Use atomic API for page flip

["Kazlauskas, Nicholas" <nicholas.kazlauskas@amd.com>]

Sorry for the delay on checking this.

I've given it a spin and on Raven/Navi I see that before applying the 
patches I get SUCCESS for all 3 subtests but after applying them every 
test fails.

Patch 1 is what breaks it, but it's hard to say whether this is a test 
bug or AMDGPU driver bug from initial investigation.

I'm seeing that the vblank_ns = last_vblank_ns so I think we're still on 
the same frame when we get the event back.

I would think this would affect userspace behavior but adaptive sync 
works fine on this kernel for games and benchmarks.

Not sure if what I was doing with wait_for_vblank works is actually 
waiting for the page flip event from the driver or just the vblank 
event. We want to be comparing the delta between the page-flip events.

Regards,
Nicholas Kazlauskas

On 2020-08-03 6:17 p.m., Navare, Manasi wrote:
> 
> @Harry and @Nicholas, could you run kms_vrr IGT with this patch on AMD
> to see that with teh atomic API, it doesnt break VRR on AMD?
> 
> Regards
> Manasi
> 
> On Wed, Jul 01, 2020 at 09:16:59PM -0700, Modem, Bhanuprakash wrote:
>>> -----Original Message-----
>>> From: Navare, Manasi D <manasi.d.navare@intel.com>
>>> Sent: Wednesday, June 3, 2020 12:41 AM
>>> To: Modem, Bhanuprakash <bhanuprakash.modem@intel.com>
>>> Cc: igt-dev@lists.freedesktop.org; harry.wentland@amd.com;
>>> nicholas.kazlauskas@amd.com; Kiran, Pichika Uday
>>> <pichika.uday.kiran@intel.com>
>>> Subject: Re: [RFC PATCH 1/2] tests/kms_vrr: Use atomic API for page flip
>>>
>>> On Mon, May 11, 2020 at 11:56:46AM +0530, bhanuprakash.modem@intel.com
>>> wrote:
>>>> From: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
>>>>
>>>> We should avoid using drmModePageFlip as it'll only be used for
>>>> legacy drivers, instead, use igt_display_commit_atomic() API to
>>>> page flip for atomic display code path.
>>>>
>>>> Cc: Harry Wentland <harry.wentland@amd.com>
>>>> Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
>>>> Cc: Manasi Navare <manasi.d.navare@intel.com>
>>>> Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
>>>
>>> I have tested this on i915 and the page flips are captured correctly with
>>> non blocking page flip requests using atomic_commit call.
>>>
>>> @Harry, @Nicholas could you test this on AMD driver to make
>>> sure its not breaking anything?
>> [Bhanu]
>> @Harry, @Nicholas did you get a chance to check this patch?
>>>
>>> Manasi
>>>
>>>> ---
>>>>   tests/kms_vrr.c | 39 ++++++++++-----------------------------
>>>>   1 file changed, 10 insertions(+), 29 deletions(-)
>>>>
>>>> diff --git a/tests/kms_vrr.c b/tests/kms_vrr.c
>>>> index 73115fef..0fe28931 100644
>>>> --- a/tests/kms_vrr.c
>>>> +++ b/tests/kms_vrr.c
>>>> @@ -126,11 +126,11 @@ static range_t get_vrr_range(data_t *data,
>>> igt_output_t *output)
>>>>   }
>>>>
>>>>   /* Returns a suitable vrr test frequency. */
>>>> -static uint32_t get_test_rate_ns(data_t *data, igt_output_t *output)
>>>> +static uint64_t get_test_rate_ns(data_t *data, igt_output_t *output)
>>>>   {
>>>>   drmModeModeInfo *mode = igt_output_get_mode(output);
>>>>   range_t range;
>>>> -uint32_t vtest;
>>>> +uint64_t vtest;
>>>>
>>>>   /*
>>>>    * The frequency with the fastest convergence speed should be
>>>> @@ -210,32 +210,18 @@ wait_for_vblank(data_t *data, enum pipe pipe)
>>>>   return get_vblank_event_ns(data);
>>>>   }
>>>>
>>>> -/* Performs an asynchronous non-blocking page-flip on a pipe. */
>>>> -static int
>>>> +/* Performs an atomic non-blocking page-flip on a pipe. */
>>>> +static void
>>>>   do_flip(data_t *data, enum pipe pipe_id, igt_fb_t *fb)
>>>>   {
>>>> -igt_pipe_t *pipe = &data->display.pipes[pipe_id];
>>>> -int ret;
>>>> -
>>>>   igt_set_timeout(1, "Scheduling page flip\n");
>>>>
>>>> -/*
>>>> - * Only the legacy flip ioctl supports async flips.
>>>> - * It's also non-blocking, but returns -EBUSY if flipping too fast.
>>>> - * 2x monitor tests will need async flips in the atomic API.
>>>> - */
>>>> -do {
>>>> -ret = drmModePageFlip(data->drm_fd, pipe->crtc_id,
>>>> -      fb->fb_id,
>>>> -      DRM_MODE_PAGE_FLIP_EVENT |
>>>> -      DRM_MODE_PAGE_FLIP_ASYNC,
>>>> -      data);
>>>> -} while (ret == -EBUSY);
>>>> -
>>>> -igt_assert_eq(ret, 0);
>>>> -igt_reset_timeout();
>>>> +igt_display_commit_atomic(&data->display,
>>>> +  DRM_MODE_ATOMIC_NONBLOCK |
>>>> +  DRM_MODE_PAGE_FLIP_EVENT,
>>>> +  NULL);
>>>>
>>>> -return 0;
>>>> +igt_reset_timeout();
>>>>   }
>>>>
>>>>   /*
>>>> @@ -246,11 +232,6 @@ do_flip(data_t *data, enum pipe pipe_id, igt_fb_t
>>> *fb)
>>>>    * can arbitrarily restrict the bounds further than the absolute
>>>>    * min and max range. But VRR is really about extending the flip
>>>>    * to prevent stuttering or to match a source content rate.
>>>> - *
>>>> - * The only way to "present" at a fixed rate like userspace in a vendor
>>>> - * neutral manner is to do it with async flips. This avoids the need
>>>> - * to wait for next vblank and it should eventually converge at the
>>>> - * desired rate.
>>>>    */
>>>>   static uint32_t
>>>>   flip_and_measure(data_t *data, igt_output_t *output, enum pipe pipe,
>>>> @@ -271,7 +252,7 @@ flip_and_measure(data_t *data, igt_output_t *output,
>>> enum pipe pipe,
>>>>   front = !front;
>>>>   do_flip(data, pipe, front ? &data->fb1 : &data->fb0);
>>>>
>>>> -vblank_ns = get_vblank_event_ns(data);
>>>> +vblank_ns = wait_for_vblank(data, pipe);
>>>>   diff_ns = rate_ns - (vblank_ns - last_vblank_ns);
>>>>   last_vblank_ns = vblank_ns;
>>>>
>>>> --
>>>> 2.24.1.1.gb6d4d82bd5
>>>>

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