drm/i915: Add some more registers to error state

Chris:
Do we also want to capture?
  GAC_ECO_BITS /* gen6,7 */
  GAM_ECOCHK /* gen6,7 */
  GAB_CTL /* gen6 */
  GFX_MODE /* gen6 */

Requested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -307,6 +307,10 @@ struct drm_i915_error_state {
 	u32 error; /* gen6+ */
 	u32 err_int; /* gen7 */
 	u32 done_reg;
+	u32 gac_eco;
+	u32 gam_ecochk;
+	u32 gab_ctl;
+	u32 gfx_mode;
 	u32 extra_instdone[I915_NUM_INSTDONE_REG];
 	u32 pipestat[I915_MAX_PIPES];
 	u64 fence[I915_MAX_NUM_FENCES];

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -1001,8 +1001,11 @@ static void i915_capture_reg_state(struct drm_i915_private *dev_priv,
 	if (IS_GEN7(dev))
 		error->err_int = I915_READ(GEN7_ERR_INT);
 
-	if (IS_GEN6(dev))
+	if (IS_GEN6(dev)) {
 		error->forcewake = I915_READ(FORCEWAKE);
+		error->gab_ctl = I915_READ(GAB_CTL);
+		error->gfx_mode = I915_READ(GFX_MODE);
+	}
 
 	if (IS_GEN2(dev))
 		error->ier = I915_READ16(IER);
@@ -1018,6 +1021,12 @@ static void i915_capture_reg_state(struct drm_i915_private *dev_priv,
 	}
 
 	/* 3: Feature specific registers */
+	if (IS_GEN6(dev) || IS_GEN7(dev)) {
+		error->gam_ecochk = I915_READ(GAM_ECOCHK);
+		error->gac_eco = I915_READ(GAC_ECO_BITS);
+	}
+
+	/* 4: Everything else */
 	if (HAS_HW_CONTEXTS(dev))
 		error->ccid = I915_READ(CCID);