drm/i915: add get_vblank_counter function for GM45

As discussed in the long thread about vblank related timeouts, it turns out
GM45 has different frame count registers than previous chips.  This patch
adds support for them, which prevents us from waiting on really stale
sequence values in drm_wait_vblank (which rather than returning immediately
ends up timing out or getting interrupted).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a70bf77290fc..7325363164f8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -535,6 +535,7 @@ extern int i915_vblank_pipe_get(struct drm_device *dev, void *data,
 extern int i915_enable_vblank(struct drm_device *dev, int crtc);
 extern void i915_disable_vblank(struct drm_device *dev, int crtc);
 extern u32 i915_get_vblank_counter(struct drm_device *dev, int crtc);
+extern u32 gm45_get_vblank_counter(struct drm_device *dev, int crtc);
 extern int i915_vblank_swap(struct drm_device *dev, void *data,
                             struct drm_file *file_priv);
 extern void i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask);