Re: [PATCH i-g-t] kms_flip_tiling: Test flips between same tiling

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 04/23/2015 11:39 AM, Chris Wilson wrote:
> On Thu, Apr 23, 2015 at 11:08:35AM +0100, Tvrtko Ursulin wrote:
>> +/*
>> + * Test that tiled page flips work.
>
> Worth saying that we don't always expect linear->tiled flips to work, so
> the mo is to first set the CRTC with a tiled fb, then flip to the
> second.

I didn't have that in mind for this test - here it only concerns itself 
with skl_do_mmio_flip bug (2ebef630fd283642a11c48c0e0f054c3c5c59e86).

>> + */
>> +static void
>> +test_tiled_flip(data_t *data, igt_output_t *output, uint64_t tiling)
>> +{
>> +	drmModeModeInfo *mode;
>> +	igt_plane_t *primary;
>> +	igt_pipe_crc_t *pipe_crc;
>> +	igt_crc_t reference_crc, crc;
>> +	struct igt_fb fb[2];
>> +	int fb_id[2], pipe, ret, width, height;
>> +
>> +	pipe = output->config.pipe;
>> +	pipe_crc = igt_pipe_crc_new(pipe, INTEL_PIPE_CRC_SOURCE_AUTO);
>> +	igt_output_set_pipe(output, pipe);
>> +
>> +	mode = igt_output_get_mode(output);
>> +	primary = igt_output_get_plane(output, 0);
>> +
>> +	width = mode->hdisplay;
>> +	height = mode->vdisplay;
>> +
>> +	/* create two identical fbs */
>> +	fb_id[0] = igt_create_fb(data->drm_fd, width, height,
>> +				 DRM_FORMAT_XRGB8888, tiling, &fb[0]);
>> +	igt_assert(fb_id[0]);
>> +
>> +	fb_id[1] = igt_create_fb(data->drm_fd, width, height,
>> +				 DRM_FORMAT_XRGB8888, tiling, &fb[1]);
>> +	igt_assert(fb_id[1]);
>> +
>> +	fill_fb(&fb[0], data, mode);
>> +	fill_fb(&fb[1], data, mode);
>
> Pretty please can we have two different patterns?
>
>> +	/* set the crtc and generate a reference crc */
>> +	igt_plane_set_fb(primary, &fb[0]);
>> +	igt_display_commit(&data->display);
>> +	igt_pipe_crc_collect_crc(pipe_crc, &reference_crc);
>> +
>> +	/* flip to the other fb */
>> +	ret = drmModePageFlip(data->drm_fd, output->config.crtc->crtc_id,
>> +			      fb_id[1], 0, NULL);
>> +	igt_assert_eq(ret, 0);
>> +
>> +	igt_wait_for_vblank(data->drm_fd, pipe);
>
> I'd be more comfortable waiting for the flip-completion event (and then
> a vblank for the CRC to be computed? idk)

I can look into that but shame on you for ruining my copy&paste party! ;)

>> +	/* get a crc and compare with the reference */
>> +	igt_pipe_crc_collect_crc(pipe_crc, &crc);
>> +	igt_assert_crc_equal(&reference_crc, &crc);
>
> With 2 patterns you can even test the second flip back again!
>
> So for detecting the current breakage, we should just a
> test_tiled_change that if PageFlip returns 0, the crc matches the
> reference? And iterate over the modes to find one that causes an
> underrun?

Underruns and watermarks I intended for another test case. This one is a 
really simple one - flip with the same framebuffer and check that it has 
really remained the same.

And the pre-existent test_flip_changes_tiling works in the opposite 
direction so won't cause an underrun. But will start failing if we merge 
(drm/i915/skl: Disallow tiling changes during page flip).

So third test case could be what you say, flip from linear to tiled and 
check for underrun if it works.

Regards,

Tvrtko
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