drm/i915: gen7: work around a system hang on IVB

commit db099c8f963fe656108e0a068274c5580a17f69b upstream.

This adds the workaround for WaCatErrorRejectionIssue which could result
in a system hang.

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>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index cbe5d01..2ae87ca 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2893,6 +2893,10 @@
 #define GEN7_L3_CHICKEN_MODE_REGISTER          0xB030
 #define  GEN7_WA_L3_CHICKEN_MODE                               0x20000000
 
+/* WaCatErrorRejectionIssue */
+#define GEN7_SQ_CHICKEN_MBCUNIT_CONFIG         0x9030
+#define  GEN7_SQ_CHICKEN_MBCUNIT_SQINTMOB      (1<<11)
+
 /* PCH */
 
 /* south display engine interrupt */

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4d1a7a7..bf3deb1 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8261,6 +8261,11 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
        I915_WRITE(GEN7_L3_CHICKEN_MODE_REGISTER,
                        GEN7_WA_L3_CHICKEN_MODE);
 
+       /* This is required by WaCatErrorRejectionIssue */
+       I915_WRITE(GEN7_SQ_CHICKEN_MBCUNIT_CONFIG,
+                       I915_READ(GEN7_SQ_CHICKEN_MBCUNIT_CONFIG) |
+                       GEN7_SQ_CHICKEN_MBCUNIT_SQINTMOB);
+
        for_each_pipe(pipe) {
                I915_WRITE(DSPCNTR(pipe),
                           I915_READ(DSPCNTR(pipe)) |