drm/i915: add FIFO watermark support

This patch from jbarnes and myself adds FIFO watermark control to the
driver.  This is needed for both power saving features on new platforms
with the so-called "big FIFO" and for controlling FIFO allocation
between pipes in multi-head configurations.

It's also necessary infrastructure to support things like framebuffer
compression and configuration supportability checks (i.e. checking a
configuration against available bandwidth).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_drv.h

@@ -225,6 +225,8 @@ typedef struct drm_i915_private {
 	int fence_reg_start; /* 4 if userland hasn't ioctl'd us yet */
 	int num_fence_regs; /* 8 on pre-965, 16 otherwise */
 
+	unsigned int fsb_freq, mem_freq;
+
 	spinlock_t error_lock;
 	struct drm_i915_error_state *first_error;
 
@@ -889,6 +891,8 @@ extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
 #define SUPPORTS_INTEGRATED_HDMI(dev)	(IS_G4X(dev) || IS_IGDNG(dev))
 #define SUPPORTS_INTEGRATED_DP(dev)	(IS_G4X(dev) || IS_IGDNG(dev))
 #define I915_HAS_HOTPLUG(dev) (IS_I945G(dev) || IS_I945GM(dev) || IS_I965G(dev))
+/* dsparb controlled by hw only */
+#define DSPARB_HWCONTROL(dev) (IS_G4X(dev))
 
 #define PRIMARY_RINGBUFFER_SIZE         (128*1024)