drm/i915: add FIFO watermark support for G4x

Turns out G4x needs to have sensible watermarks set, especially for
self-refresh enabled modes.  Add support for it.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Dirk Hohndel <hohndel@infradead.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 78f336e..1687edf 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1799,17 +1799,29 @@
 #define   DSPARB_AEND_SHIFT	0
 
 #define DSPFW1			0x70034
+#define   DSPFW_SR_SHIFT	23
+#define   DSPFW_CURSORB_SHIFT	16
+#define   DSPFW_PLANEB_SHIFT	8
 #define DSPFW2			0x70038
+#define   DSPFW_CURSORA_MASK	0x00003f00
+#define   DSPFW_CURSORA_SHIFT	16
 #define DSPFW3			0x7003c
+#define   DSPFW_HPLL_SR_EN	(1<<31)
+#define   DSPFW_CURSOR_SR_SHIFT	24
 #define   IGD_SELF_REFRESH_EN	(1<<30)
 
 /* FIFO watermark sizes etc */
+#define G4X_FIFO_LINE_SIZE	64
 #define I915_FIFO_LINE_SIZE	64
 #define I830_FIFO_LINE_SIZE	32
+
+#define G4X_FIFO_SIZE		127
 #define I945_FIFO_SIZE		127 /* 945 & 965 */
 #define I915_FIFO_SIZE		95
 #define I855GM_FIFO_SIZE	127 /* In cachelines */
 #define I830_FIFO_SIZE		95
+
+#define G4X_MAX_WM		0x3f
 #define I915_MAX_WM		0x3f
 
 #define IGD_DISPLAY_FIFO	512 /* in 64byte unit */