drm/i915: don't access FW_BLC_SELF on 965G

The register offset for FW_BLC_SELF is a totally different set of bits
on Broadwater (it's actually MI_RDRET_STATE), so don't treat it like
FW_BLC_SELF on 965G chips.

Fixes bug https://bugs.freedesktop.org/show_bug.cgi?id=26874.

Cc: stable@kernel.org
Tested-by: Norman Yarvin <yarvin@yarchive.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -620,7 +620,7 @@ static int i915_sr_status(struct seq_file *m, void *unused)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	bool sr_enabled = false;
 
-	if (IS_I965G(dev) || IS_I945G(dev) || IS_I945GM(dev))
+	if (IS_I965GM(dev) || IS_I945G(dev) || IS_I945GM(dev))
 		sr_enabled = I915_READ(FW_BLC_SELF) & FW_BLC_SELF_EN;
 	else if (IS_I915GM(dev))
 		sr_enabled = I915_READ(INSTPM) & INSTPM_SELF_EN;

drivers/gpu/drm/i915/intel_display.c

@@ -2970,11 +2970,13 @@ static void i965_update_wm(struct drm_device *dev, int planea_clock,
 		if (srwm < 0)
 			srwm = 1;
 		srwm &= 0x3f;
-		I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);
+		if (IS_I965GM(dev))
+			I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);
 	} else {
 		/* Turn off self refresh if both pipes are enabled */
-		I915_WRITE(FW_BLC_SELF, I915_READ(FW_BLC_SELF)
-					& ~FW_BLC_SELF_EN);
+		if (IS_I965GM(dev))
+			I915_WRITE(FW_BLC_SELF, I915_READ(FW_BLC_SELF)
+				   & ~FW_BLC_SELF_EN);
 	}
 
 	DRM_DEBUG_KMS("Setting FIFO watermarks - A: 8, B: 8, C: 8, SR %d\n",