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>

5 files changed, 24 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 0ded483d9ac..81f1cff56fd 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1112,6 +1112,10 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	dev_priv->has_gem = 1;
 #endif
 
+	dev->driver->get_vblank_counter = i915_get_vblank_counter;
+	if (IS_GM45(dev))
+		dev->driver->get_vblank_counter = gm45_get_vblank_counter;
+
 	i915_gem_load(dev);
 
 	/* Init HWS */
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index f8b3df0926c..aac12ee31a4 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -112,7 +112,6 @@ static struct drm_driver driver = {
 	.suspend = i915_suspend,
 	.resume = i915_resume,
 	.device_is_agp = i915_driver_device_is_agp,
-	.get_vblank_counter = i915_get_vblank_counter,
 	.enable_vblank = i915_enable_vblank,
 	.disable_vblank = i915_disable_vblank,
 	.irq_preinstall = i915_driver_irq_preinstall,
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a70bf77290f..7325363164f 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);
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6290219de6c..548ff2c6643 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -174,6 +174,19 @@ u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
 	return count;
 }
 
+u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
+{
+	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+	int reg = pipe ? PIPEB_FRMCOUNT_GM45 : PIPEA_FRMCOUNT_GM45;
+
+	if (!i915_pipe_enabled(dev, pipe)) {
+		DRM_ERROR("trying to get vblank count for disabled pipe %d\n", pipe);
+		return 0;
+	}
+
+	return I915_READ(reg);
+}
+
 irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 928e0046257..9d6539a868b 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1371,6 +1371,9 @@
 #define   PIPE_FRAME_LOW_SHIFT    24
 #define   PIPE_PIXEL_MASK         0x00ffffff
 #define   PIPE_PIXEL_SHIFT        0
+/* GM45+ just has to be different */
+#define PIPEA_FRMCOUNT_GM45	0x70040
+#define PIPEA_FLIPCOUNT_GM45	0x70044
 
 /* Cursor A & B regs */
 #define CURACNTR		0x70080
@@ -1439,6 +1442,9 @@
 #define PIPEBSTAT		0x71024
 #define PIPEBFRAMEHIGH		0x71040
 #define PIPEBFRAMEPIXEL		0x71044
+#define PIPEB_FRMCOUNT_GM45	0x71040
+#define PIPEB_FLIPCOUNT_GM45	0x71044
+
 
 /* Display B control */
 #define DSPBCNTR		0x71180