[Intel-gfx] [PATCH] drm/i915/gt: Disable HiZ Raw Stall Optimization on broken gen7

[Simon Rettberg]

When resetting CACHE_MODE registers, don't enable HiZ Raw Stall
Optimization on Ivybridge GT1 and Baytrail, as it causes severe glitches
when rendering any kind of 3D accelerated content.
This optimization is disabled on these platforms by default according to
official documentation from 01.org.

Fixes: ef99a60ffd9b ("drm/i915/gt: Clear CACHE_MODE prior to clearing residuals")
Fixes: 520d05a77b28 ("drm/i915/gt: Clear CACHE_MODE prior to clearing residuals")
BugLink: https://gitlab.freedesktop.org/drm/intel/-/issues/3081
BugLink: https://gitlab.freedesktop.org/drm/intel/-/issues/3404
BugLink: https://gitlab.freedesktop.org/drm/intel/-/issues/3071
Reviewed-By: Manuel Bentele <development at manuel-bentele.de>
Signed-off-by: Simon Rettberg <simon.rettberg at rz.uni-freiburg.de>
---
 drivers/gpu/drm/i915/gt/gen7_renderclear.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/gen7_renderclear.c b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
index de575fdb0..21f08e538 100644
--- a/drivers/gpu/drm/i915/gt/gen7_renderclear.c
+++ b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
@@ -397,7 +397,10 @@ static void emit_batch(struct i915_vma * const vma,
 	gen7_emit_pipeline_invalidate(&cmds);
 	batch_add(&cmds, MI_LOAD_REGISTER_IMM(2));
 	batch_add(&cmds, i915_mmio_reg_offset(CACHE_MODE_0_GEN7));
-	batch_add(&cmds, 0xffff0000);
+	batch_add(&cmds, 0xffff0000 |
+			((IS_IVB_GT1(i915) || IS_VALLEYVIEW(i915)) ?
+			 HIZ_RAW_STALL_OPT_DISABLE :
+			 0));
 	batch_add(&cmds, i915_mmio_reg_offset(CACHE_MODE_1));
 	batch_add(&cmds, 0xffff0000 | PIXEL_SUBSPAN_COLLECT_OPT_DISABLE);
 	gen7_emit_pipeline_invalidate(&cmds);
-- 
2.25.1