On 07/15, Arkadiusz Hiler wrote: > On Mon, Jun 22, 2020 at 01:38:26PM -0300, Melissa Wen wrote: > > When running subtests in sequence using vkms, the beginning of CRC capture > > process does not match the simulated vblank timing. This mismatch leads to > > an endless busy wait and, consequently, timeout failures for the remaining > > subtests in the test sequence. This patch sets the pace by waiting for > > vblank before starting the CRC capture. > > > > Signed-off-by: Melissa Wen <melissa....@gmail.com> > > This one is quite interetesing. The test seems to be working just fine > on the real hardware and causes the endless busy wait on VKMS only... > > DRM is bad at describing usage sequences and what's defined and what's > undefined when it comes to behavior. We just try not to break any of the > existing users. On top of that CRC capture is a testing/debug feature > that doesn't have have to be stable - it's not really obvious what's the > correct course of action here. > > The vblank wait won't harm anyone, especially in the context presented > above. You have to keep in mind that other implementations of CRC > caputring doesn't have that requirement and you will likely find more > similar instances of this usage pattern. There may be even more of them > introduced over time - there's no CI on VKMS (fingers crossed that this > is going to change). > > Have you thought about what's easier here - making the current code work > on the VKMS side or fixing the test? I would like to know your thoughts > on this. Hi,
Thank you very much for the review! I've been investigating more about this with the community help and, in fact, the problem seems to be more linked to vkms. I mean, this problem of waiting for a vblank before starting to capture the CRC seems to affect vkms in other igt tests too. So the most accurate thing is to treat it over there. I will send a v2 only with the other patch that releases the pipe_crc before creating a new one. Thanks again, Melissa > > -- > Cheers, > Arek > > > > > > --- > > tests/kms_cursor_crc.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/tests/kms_cursor_crc.c b/tests/kms_cursor_crc.c > > index 5976df5f..755c34ed 100644 > > --- a/tests/kms_cursor_crc.c > > +++ b/tests/kms_cursor_crc.c > > @@ -474,6 +474,7 @@ static void prepare_crtc(data_t *data, igt_output_t > > *output, > > igt_assert(data->batch); > > } > > > > + igt_wait_for_vblank(data->drm_fd, data->pipe); > > igt_pipe_crc_start(data->pipe_crc); > > } > > > > -- > > 2.27.0 > > > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
