drm/i915: gen7: Disable the RHWO optimization as it can cause GPU hangs.

commit d71de14ddf423ccc9a2e3f7e37553c99ead20d7c upstream.

The BSpec Workarounds page states that bits 10 and 26 must be set to
avoid 3D ring hangs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41353
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44610
Tested-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ed679d04bbb..56315cbef1e 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2848,6 +2848,9 @@
 #define  DISP_FBC_WM_DIS                (1<<15)
 
 /* GEN7 chicken */
+#define GEN7_COMMON_SLICE_CHICKEN1              0x7010
+# define GEN7_CSC1_RHWO_OPT_DISABLE_IN_RCC      ((1<<10) | (1<<26))
+
 #define GEN7_L3CNTLREG1                         0xB01C
 #define  GEN7_WA_FOR_GEN7_L3_CONTROL                    0x3C4FFF8C
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index aac61b2849f..57f90437d08 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7464,6 +7464,10 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
 
         I915_WRITE(ILK_DSPCLK_GATE, IVB_VRHUNIT_CLK_GATE);
 
+        /* Apply the WaDisableRHWOOptimizationForRenderHang workaround. */
+        I915_WRITE(GEN7_COMMON_SLICE_CHICKEN1,
+                   GEN7_CSC1_RHWO_OPT_DISABLE_IN_RCC);
+
         /* WaApplyL3ControlAndL3ChickenMode requires those two on Ivy Bridge */
         I915_WRITE(GEN7_L3CNTLREG1,
                         GEN7_WA_FOR_GEN7_L3_CONTROL);