From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
On i965gm we need to adjust max_vblank_count dynamically
depending on whether the TV encoder is used or not. To
that end add a per-crtc max_vblank_count that takes
precedence over its device wide counterpart. The driver
can now call drm_crtc_set_max_vblank_count() to configure
the per-crtc value before calling drm_vblank_on().
Also looks like there was some discussion about exynos needing
similar treatment.
Cc: stable@xxxxxxxxxxxxxxx
Cc: Inki Dae <inki.dae@xxxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_vblank.c | 39 ++++++++++++++++++++++++++++++++----
include/drm/drm_vblank.h | 8 ++++++++
2 files changed, 43 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 98e091175921..c3abbdca8aba 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -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));
@@ -258,7 +266,8 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
pipe, vblank->count, diff, cur_vblank, vblank->last);
if (diff == 0) {
- WARN_ON_ONCE(cur_vblank != vblank->last);
+ WARN_ON_ONCE(max_vblank_count &&
+ cur_vblank != vblank->last);
return;
}
@@ -1204,6 +1213,28 @@ 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. Useful
+ * for hardware where the operation of the hardware vblank counter
+ * depends on the active display configuration.
+ *
+ * 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];
+
+ 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
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
index 6ad9630d4f48..ecb2cf9913e2 100644
--- a/include/drm/drm_vblank.h
+++ b/include/drm/drm_vblank.h
@@ -128,6 +128,12 @@ struct drm_vblank_crtc {
* @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
*/
u32 last;
+ /**
+ * @max_vblank_count: Maximum value of the hardware vblank counter.
+ * If non-zero this takes precedence over &drm_device.max_vblank_count
+ * for this crtc. Otherwise &drm_device.max_vblank_count is used.
+ */
+ u32 max_vblank_count;
/**
* @inmodeset: Tracks whether the vblank is disabled due to a modeset.
* For legacy driver bit 2 additionally tracks whether an additional
@@ -206,4 +212,6 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
void drm_calc_timestamping_constants(struct drm_crtc *crtc,
const struct drm_display_mode *mode);
wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
+void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
+ u32 max_vblank_count);
#endif
--
2.18.1
