drm/radeon/kms: display watermark updates (v2)

- Add module option to force the display priority
  0 = auto, 1 = normal, 2 = high
- Default to high on r3xx/r4xx/rv515 chips
  Fixes flickering problems during heavy acceleration
  due to underflow to the display controllers
- Fill in minimal support for RS600

v2 - update display priority when bandwidth is updated
so the user can change the parameter at runtime and it
will take affect on the next modeset.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/rs690d.h b/drivers/gpu/drm/radeon/rs690d.h
index 62d31e7..36e6398 100644
--- a/drivers/gpu/drm/radeon/rs690d.h
+++ b/drivers/gpu/drm/radeon/rs690d.h
@@ -182,6 +182,9 @@
 #define   S_006548_D1MODE_PRIORITY_A_OFF(x)            (((x) & 0x1) << 16)
 #define   G_006548_D1MODE_PRIORITY_A_OFF(x)            (((x) >> 16) & 0x1)
 #define   C_006548_D1MODE_PRIORITY_A_OFF               0xFFFEFFFF
+#define   S_006548_D1MODE_PRIORITY_A_ALWAYS_ON(x)      (((x) & 0x1) << 20)
+#define   G_006548_D1MODE_PRIORITY_A_ALWAYS_ON(x)      (((x) >> 20) & 0x1)
+#define   C_006548_D1MODE_PRIORITY_A_ALWAYS_ON         0xFFEFFFFF
 #define   S_006548_D1MODE_PRIORITY_A_FORCE_MASK(x)     (((x) & 0x1) << 24)
 #define   G_006548_D1MODE_PRIORITY_A_FORCE_MASK(x)     (((x) >> 24) & 0x1)
 #define   C_006548_D1MODE_PRIORITY_A_FORCE_MASK        0xFEFFFFFF