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path: root/drivers/gpu/drm/drm_vblank.c
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Diffstat (limited to 'drivers/gpu/drm/drm_vblank.c')
-rw-r--r--drivers/gpu/drm/drm_vblank.c47
1 files changed, 43 insertions, 4 deletions
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 98e091175921..a1b65d26d761 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -48,7 +48,7 @@
* Drivers must initialize the vertical blanking handling core with a call to
* drm_vblank_init(). Minimally, a driver needs to implement
* &drm_crtc_funcs.enable_vblank and &drm_crtc_funcs.disable_vblank plus call
- * drm_crtc_handle_vblank() in it's vblank interrupt handler for working vblank
+ * drm_crtc_handle_vblank() in its vblank interrupt handler for working vblank
* support.
*
* Vertical blanking interrupts can be enabled by the DRM core or by drivers
@@ -105,13 +105,20 @@ static void store_vblank(struct drm_device *dev, unsigned int pipe,
write_sequnlock(&vblank->seqlock);
}
+static u32 drm_max_vblank_count(struct drm_device *dev, unsigned int pipe)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+ return vblank->max_vblank_count ?: dev->max_vblank_count;
+}
+
/*
* "No hw counter" fallback implementation of .get_vblank_counter() hook,
* if there is no useable hardware frame counter available.
*/
static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
{
- WARN_ON_ONCE(dev->max_vblank_count != 0);
+ WARN_ON_ONCE(drm_max_vblank_count(dev, pipe) != 0);
return 0;
}
@@ -198,6 +205,7 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
ktime_t t_vblank;
int count = DRM_TIMESTAMP_MAXRETRIES;
int framedur_ns = vblank->framedur_ns;
+ u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
/*
* Interrupts were disabled prior to this call, so deal with counter
@@ -216,9 +224,9 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
- if (dev->max_vblank_count != 0) {
+ if (max_vblank_count) {
/* trust the hw counter when it's around */
- diff = (cur_vblank - vblank->last) & dev->max_vblank_count;
+ diff = (cur_vblank - vblank->last) & max_vblank_count;
} else if (rc && framedur_ns) {
u64 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
@@ -1205,6 +1213,37 @@ void drm_crtc_vblank_reset(struct drm_crtc *crtc)
EXPORT_SYMBOL(drm_crtc_vblank_reset);
/**
+ * drm_crtc_set_max_vblank_count - configure the hw max vblank counter value
+ * @crtc: CRTC in question
+ * @max_vblank_count: max hardware vblank counter value
+ *
+ * Update the maximum hardware vblank counter value for @crtc
+ * at runtime. Useful for hardware where the operation of the
+ * hardware vblank counter depends on the currently active
+ * display configuration.
+ *
+ * For example, if the hardware vblank counter does not work
+ * when a specific connector is active the maximum can be set
+ * to zero. And when that specific connector isn't active the
+ * maximum can again be set to the appropriate non-zero value.
+ *
+ * If used, must be called before drm_vblank_on().
+ */
+void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
+ u32 max_vblank_count)
+{
+ struct drm_device *dev = crtc->dev;
+ unsigned int pipe = drm_crtc_index(crtc);
+ struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+
+ WARN_ON(dev->max_vblank_count);
+ WARN_ON(!READ_ONCE(vblank->inmodeset));
+
+ vblank->max_vblank_count = max_vblank_count;
+}
+EXPORT_SYMBOL(drm_crtc_set_max_vblank_count);
+
+/**
* drm_crtc_vblank_on - enable vblank events on a CRTC
* @crtc: CRTC in question
*