[igt-dev] [PATCH i-g-t v2 1/2] tests/frontbuffer_tracking: Do not assert FBC state after a page flip changing stride

[Dhinakaran Pandiyan]

On Tue, 2019-04-02 at 13:59 -0700, José Roberto de Souza wrote:
> When the stridechange subtest was introduced f23ea58f1fbb
> ("kms_frontbuffer_tracking: expand badstride and stridechange")
> atomic was not around and change the stride using drmModePageFlip()
> was not allowed so it was expected that it would return -EINVAL and
> kernel would keep the old framebuffer with the smaller plane that is
> know to fit on CFB(if it don't fit the test will skip on the first
> full-modeset because "not enough stolen memory" is set).
> 
> But after the introduction of atomic the subtest was updated by
> f63e070b469d ("kms_frontbuffer_tracking: Fix tests with the new
> atomic reality.") to accept a no error return from drmModePageFlip()
> but the do_assertions() that follows it was not updated.
> As the subtest function comment states, kernel will do fastsets in
> this scenario and the allocated CFB could not be enough to keep FBC
> enabled over the new framebuffer, so here adding the missing
> DONT_ASSERT_FEATURE_STATUS to ignore the FBC state and just test if
> CRC match and if kernel do not misbehave.
> 
> Other way to solve this issue would be make the kernel do a
> full-modeset when CFB is not enough for the new plane so FBC is
> disabled with the CRC freeing the actual CFB and then after enable
> CRTC again it will try to enable FBC again if it can allocate the
> required CFB but by the subtest comment this is not intended.
> 
> v2: Assert features when drmModePageFlip() fails aka non-atomic
> driver(Dhinakaran)
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105683
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  tests/kms_frontbuffer_tracking.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tests/kms_frontbuffer_tracking.c
> b/tests/kms_frontbuffer_tracking.c
> index 89586326..caef6755 100644
> --- a/tests/kms_frontbuffer_tracking.c
> +++ b/tests/kms_frontbuffer_tracking.c
> @@ -2932,7 +2932,7 @@ static void stridechange_subtest(const struct test_mode
> *t)
>  	 */
>  	rc = drmModePageFlip(drm.fd, drm.display.pipes[params->pipe].crtc_id,
> new_fb->fb_id, 0, NULL);
>  	igt_assert(rc == -EINVAL || rc == 0);
> -	do_assertions(0);
> +	do_assertions(rc ? 0 : DONT_ASSERT_FEATURE_STATUS);

Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>


>  }
>  
>  /**