[Intel-gfx] [PATCH igt] tests/kms_flip: Make flip-vs-panning-vs-hang change DSPSURF

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Make sure DSPSURF will change during the panning operation
in flip-vs-panning-vs-hang.

This will now test agains bugs between the kernel's mmio vs.
CS flip race handling and GPU resets. If the kernel is buggy
if will fail to notice that the panning operation changed the
base address before the GPU reset had a chance to deal with the
pending page flips, and so the flip would never complete due to
DSPSURFLIVE not matching the expected value.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 tests/kms_flip.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/kms_flip.c b/tests/kms_flip.c
index dd64182..6711f09 100644
--- a/tests/kms_flip.c
+++ b/tests/kms_flip.c
@@ -923,6 +923,10 @@ static unsigned int run_test_step(struct test_output *o)
 			o->flip_state.count : o->vblank_state.count;
 		int x_ofs = count * 10 > o->fb_width - o->kmode[0].hdisplay ? o->fb_width - o->kmode[0].hdisplay : count * 10;
 
+		/* Make sure DSPSURF changes value */
+		if (o->flags & TEST_HANG)
+			o->current_fb_id = !o->current_fb_id;
+
 		igt_assert_f(set_mode(o, o->fb_ids[o->current_fb_id], x_ofs, 0) == 0,
 			     "failed to pan (%dx%d@%dHz)+%d: %s\n",
 			     o->kmode[0].hdisplay, o->kmode[0].vdisplay, o->kmode[0].vrefresh,
-- 
1.8.5.5