[igt-dev] [PATCH i-g-t] tests/kms_async_flips: Add CRC test to make sure the correct fb is being scanned out
Karthik B S
karthik.b.s at intel.com
Thu May 6 04:56:32 UTC 2021
On 5/5/2021 5:28 PM, Ville Syrjälä wrote:
> On Wed, May 05, 2021 at 09:02:42AM +0530, Karthik B S wrote:
>> On 3/4/2021 9:20 PM, Ville Syrjala wrote:
>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>
>>> Use CRC to confirm that the old fb is no longer being scanned
>>> out after the async flip completes. We do this by immediately
>>> rendering garbage into the old fb after receiving the flip
>>> event. Should fail if someone is improperly using mailbox style
>>> flips while claiming to do async flips.
>>>
>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>> ---
>>> tests/kms_async_flips.c | 135 ++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 135 insertions(+)
>>>
>>> diff --git a/tests/kms_async_flips.c b/tests/kms_async_flips.c
>>> index e397a54b874f..bc0f95b9ebf6 100644
>>> --- a/tests/kms_async_flips.c
>>> +++ b/tests/kms_async_flips.c
>>> @@ -52,6 +52,11 @@ typedef struct {
>>> drmModeConnectorPtr connector;
>>> unsigned long flip_timestamp_us;
>>> double flip_interval;
>>> + igt_pipe_crc_t *pipe_crc;
>>> + igt_crc_t ref_crc;
>>> + int flip_count;
>>> + int frame_count;
>>> + bool flip_pending;
>>> } data_t;
>>>
>>> static drmModeConnectorPtr find_connector_for_modeset(data_t *data)
>>> @@ -379,6 +384,132 @@ static void test_init(data_t *data)
>>> drmModeFreeResources(res);
>>> }
>>>
>>> +static void queue_vblank(data_t *data)
>>> +{
>>> + drmVBlank wait_vbl = {
>>> + .request.type = DRM_VBLANK_RELATIVE | DRM_VBLANK_EVENT |
>>> + kmstest_get_pipe_from_crtc_id(data->drm_fd, data->crtc_id),
>>> + .request.sequence = 1,
>>> + .request.signal = (long)data,
>>> + };
>>> +
>>> + igt_assert(drmIoctl(data->drm_fd, DRM_IOCTL_WAIT_VBLANK, &wait_vbl) == 0);
>>> +}
>>> +
>>> +static void vblank_handler_crc(int fd_, unsigned int sequence, unsigned int tv_sec,
>>> + unsigned int tv_usec, void *_data)
>>> +{
>>> + data_t *data = _data;
>>> + igt_crc_t crc;
>>> +
>>> + data->frame_count++;
>>> +
>>> + igt_pipe_crc_get_single(data->pipe_crc, &crc);
>>> + igt_assert_crc_equal(&data->ref_crc, &crc);
>>> +
>>> + /* check again next vblank */
>>> + queue_vblank(data);
>>> +}
>>> +
>>> +static void flip_handler_crc(int fd_, unsigned int sequence, unsigned int tv_sec,
>>> + unsigned int tv_usec, void *_data)
>>> +{
>>> + data_t *data = _data;
>>> +
>>> + data->flip_pending = false;
>>> + data->flip_count++;
>>> +}
>>> +
>>> +static void wait_events_crc(data_t *data)
>>> +{
>>> + drmEventContext evctx = {
>>> + .version = 2,
>>> + .vblank_handler = vblank_handler_crc,
>>> + .page_flip_handler = flip_handler_crc,
>>> + };
>>> +
>>> + while (data->flip_pending) {
>>> + struct pollfd pfd = {
>>> + .fd = data->drm_fd,
>>> + .events = POLLIN,
>>> + };
>>> + int ret;
>>> +
>>> + ret = poll(&pfd, 1, 2000);
>>> +
>>> + switch (ret) {
>>> + case 0:
>>> + igt_assert_f(0, "Flip Timeout\n");
>>> + break;
>>> + case 1:
>>> + ret = drmHandleEvent(data->drm_fd, &evctx);
>>> + igt_assert(ret == 0);
>>> + break;
>>> + default:
>>> + /* unexpected */
>>> + igt_assert(0);
>>> + }
>>> + }
>>> +}
>>> +
>>> +static unsigned int clock_ms(void)
>>> +{
>>> + struct timespec ts;
>>> +
>>> + clock_gettime(CLOCK_MONOTONIC, &ts);
>>> +
>>> + return ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
>>> +}
>>> +
>>> +static void test_crc(data_t *data)
>>> +{
>>> + unsigned int frame = 0;
>>> + unsigned int start;
>>> + int ret;
>>> +
>>> + data->flip_count = 0;
>>> + data->frame_count = 0;
>>> + data->flip_pending = false;
>>> +
>>> + igt_draw_fill_fb(data->drm_fd, &data->bufs[frame], 0xff0000ff);
>>> + ret = drmModeSetCrtc(data->drm_fd, data->crtc_id, data->bufs[frame].fb_id, 0, 0,
>>> + &data->connector->connector_id, 1, &data->connector->modes[0]);
>>> + igt_assert_eq(ret, 0);
>>> +
>>> + data->pipe_crc = igt_pipe_crc_new(data->drm_fd,
>>> + kmstest_get_pipe_from_crtc_id(data->drm_fd, data->crtc_id),
>>> + INTEL_PIPE_CRC_SOURCE_AUTO);
>>> +
>>> + igt_pipe_crc_start(data->pipe_crc);
>>> + igt_pipe_crc_get_single(data->pipe_crc, &data->ref_crc);
>>> +
>>> + queue_vblank(data);
>>> +
>>> + start = clock_ms();
>>> +
>>> + while (clock_ms() - start < 2000) {
>>> + /* fill the next fb with the expected color */
>>> + igt_draw_fill_fb(data->drm_fd, &data->bufs[frame], 0xff0000ff);
>>> +
>>> + data->flip_pending = true;
>>> + ret = drmModePageFlip(data->drm_fd, data->crtc_id, data->bufs[frame].fb_id,
>>> + DRM_MODE_PAGE_FLIP_ASYNC | DRM_MODE_PAGE_FLIP_EVENT, data);
>>> + igt_assert_eq(ret, 0);
>>> +
>>> + wait_events_crc(data);
>>> +
>>> + /* clobber the previous fb which should no longer be scanned out */
>>> + frame = !frame;
>> Hi,
>>
>> As mentioned in the commit message, we are trying to render garbage to
>> the old fb after flip events are completed.
>> But here the frame variable is already updated before filling it with
>> garbage.
>> This means we're filling this garbage on new fb and then we again fill
>> the same fb with green in the start of the while loop before submitting
>> the next flip?
>> Is my understanding above correct? If not, could you please let me know
>> what I'm missing here?
> We're trying to see if writing garbage to the fb which is not
> supposedly being scanned out results in a crc change. And
> before we actually flip back to that fb we need to get rid of
> the garbage again and replace it with the correct color.
>
> This should fail if the hardware/driver lies about supporting
> async flips and actually fakes it using mailbox flips because
> we will end up writing garbage into the current scanout buffer.
Thank you for the clarification. Now it makes sense why I was getting
CRC mismatch when I tried the other way around.
This patch looks good to me.
Reviewed-by: Karthik B S <karthik.b.s at intel.com>
>
>> I tried to run it on my local setup by moving the the frame variable
>> update after the fill_fb below, but we see a CRC mismatch in that case.
>> So I think I'm missing something here. But not sure what I'm missing.
>>
>> Thanks,
>>
>> Karthik.B.S
>>
>>> + igt_draw_fill_fb(data->drm_fd, &data->bufs[frame], rand());
>>> + }
>>> +
>>> + igt_pipe_crc_stop(data->pipe_crc);
>>> + igt_pipe_crc_free(data->pipe_crc);
>>> +
>>> + /* make sure we got at a reasonable number of async flips done */
>>> + igt_assert_lt(data->frame_count * 2, data->flip_count);
>>> +}
>>> +
>>> igt_main
>>> {
>>> static data_t data;
>>> @@ -419,6 +550,10 @@ igt_main
>>> igt_subtest("invalid-async-flip")
>>> test_invalid(&data);
>>>
>>> + igt_describe("Use CRC to verify async flip scans out the correct framebuffer");
>>> + igt_subtest("crc")
>>> + test_crc(&data);
>>> +
>>> igt_fixture {
>>> for (i = 0; i < ARRAY_SIZE(data.bufs); i++)
>>> igt_remove_fb(data.drm_fd, &data.bufs[i]);
>>> --
>>> 2.26.2
>>>
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