The new callback get_scanout_position() reads the current location
of the scanout process. The operation is currently located in struct
drm_driver, but really belongs to the CRTC. Drivers will be converted
in separate patches.
To help with the conversion, the timestamp calculation has been
moved from drm_calc_vbltimestamp_from_scanoutpos() to
drm_crtc_vblank_helper_get_vblank_timestamp_internal(). The helper
function supports the new and old interface of get_scanout_position().
drm_calc_vbltimestamp_from_scanoutpos() remains as a wrapper around
the new function.
Callback functions return the scanout position from the CRTC. The
legacy version of the interface receives the device and pipe index,
the modern version receives a pointer to the CRTC. We keep the
legacy version until all drivers have been converted.
v3:
* refactor drm_calc_vbltimestamp_from_scanoutpos() to minimize
code duplication
* define types for get_scanout_position() callbacks
v2:
* fix logical op in drm_calc_vbltimestamp_from_scanoutpos()
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Tested-by: Yannick Fertré <yannick.fertre@xxxxxx>
---
drivers/gpu/drm/drm_vblank.c | 101 +++++++++++++++++++----
include/drm/drm_drv.h | 7 +-
include/drm/drm_modeset_helper_vtables.h | 47 +++++++++++
include/drm/drm_vblank.h | 22 +++++
4 files changed, 154 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 326db52f2ad8..7e962c29780c 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -30,6 +30,7 @@
#include <drm/drm_crtc.h>
#include <drm/drm_drv.h>
#include <drm/drm_framebuffer.h>
+#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>
@@ -577,7 +578,7 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
* Implements calculation of exact vblank timestamps from given drm_display_mode
* timings and current video scanout position of a CRTC. This can be directly
* used as the &drm_driver.get_vblank_timestamp implementation of a kms driver
- * if &drm_driver.get_scanout_position is implemented.
+ * if &drm_crtc_helper_funcs.get_scanout_position is implemented.
*
* The current implementation only handles standard video modes. For double scan
* and interlaced modes the driver is supposed to adjust the hardware mode
@@ -599,28 +600,85 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
ktime_t *vblank_time,
bool in_vblank_irq)
{
- struct timespec64 ts_etime, ts_vblank_time;
- ktime_t stime, etime;
- bool vbl_status;
struct drm_crtc *crtc;
- const struct drm_display_mode *mode;
- struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
- int vpos, hpos, i;
- int delta_ns, duration_ns;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return false;
crtc = drm_crtc_from_index(dev, pipe);
+ if (!crtc)
+ return false;
- if (pipe >= dev->num_crtcs || !crtc) {
+ return drm_crtc_vblank_helper_get_vblank_timestamp_internal(crtc,
+ max_error,
+ vblank_time,
+ in_vblank_irq,
+ crtc->helper_private->get_scanout_position,
+ dev->driver->get_scanout_position);
+}
+EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
+
+/**
+ * drm_crtc_vblank_helper_get_vblank_timestamp_internal - precise vblank
+ * timestamp helper
+ * @dev: DRM device
+ * @pipe: index of CRTC whose vblank timestamp to retrieve
+ * @max_error: Desired maximum allowable error in timestamps (nanosecs)
+ * On return contains true maximum error of timestamp
+ * @vblank_time: Pointer to time which should receive the timestamp
+ * @in_vblank_irq:
+ * True when called from drm_crtc_handle_vblank(). Some drivers
+ * need to apply some workarounds for gpu-specific vblank irq quirks
+ * if flag is set.
+ * @get_scanout_position:
+ * Callback function to retrieve the scanout position. See
+ * @struct drm_crtc_helper_funcs.get_scanout_position.
+ * @get_scanout_position_legacy:
+ * Callback function to retrieve the scanout position. See
+ * @struct drm_driver.get_scanout_position.
+ *
+ * Implements calculation of exact vblank timestamps from given drm_display_mode
+ * timings and current video scanout position of a CRTC.
+ *
+ * The current implementation only handles standard video modes. For double scan
+ * and interlaced modes the driver is supposed to adjust the hardware mode
+ * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
+ * match the scanout position reported.
+ *
+ * Note that atomic drivers must call drm_calc_timestamping_constants() before
+ * enabling a CRTC. The atomic helpers already take care of that in
+ * drm_atomic_helper_update_legacy_modeset_state().
+ *
+ * Returns:
+ *
+ * Returns true on success, and false on failure, i.e. when no accurate
+ * timestamp could be acquired.
+ */
+bool
+drm_crtc_vblank_helper_get_vblank_timestamp_internal(
+ struct drm_crtc *crtc, int *max_error, ktime_t *vblank_time,
+ bool in_vblank_irq,
+ drm_vblank_get_scanout_position_func get_scanout_position,
+ drm_vblank_get_scanout_position_legacy_func get_scanout_position_legacy)
+{
+ struct drm_device *dev = crtc->dev;
+ unsigned int pipe = crtc->index;
+ struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+ struct timespec64 ts_etime, ts_vblank_time;
+ ktime_t stime, etime;
+ bool vbl_status;
+ const struct drm_display_mode *mode;
+ int vpos, hpos, i;
+ int delta_ns, duration_ns;
+
+ if (pipe >= dev->num_crtcs) {
DRM_ERROR("Invalid crtc %u\n", pipe);
return false;
}
/* Scanout position query not supported? Should not happen. */
- if (!dev->driver->get_scanout_position) {
- DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
+ if (!get_scanout_position && !get_scanout_position_legacy) {
+ DRM_ERROR("Called from CRTC w/o get_scanout_position()!?\n");
return false;
}
@@ -635,7 +693,6 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
if (mode->crtc_clock == 0) {
DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
-
return false;
}
@@ -651,11 +708,19 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
* Get vertical and horizontal scanout position vpos, hpos,
* and bounding timestamps stime, etime, pre/post query.
*/
- vbl_status = dev->driver->get_scanout_position(dev, pipe,
- in_vblank_irq,
- &vpos, &hpos,
- &stime, &etime,
- mode);
+ if (get_scanout_position) {
+ vbl_status = get_scanout_position(crtc,
+ in_vblank_irq,
+ &vpos, &hpos,
+ &stime, &etime,
+ mode);
+ } else {
+ vbl_status = get_scanout_position_legacy(dev, pipe,
+ in_vblank_irq,
+ &vpos, &hpos,
+ &stime, &etime,
+ mode);
+ }
/* Return as no-op if scanout query unsupported or failed. */
if (!vbl_status) {
@@ -707,7 +772,7 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
return true;
}
-EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
+EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal);
/**
* drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index cf13470810a5..d0049e5786fc 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -362,11 +362,8 @@ struct drm_driver {
* True on success, false if a reliable scanout position counter could
* not be read out.
*
- * FIXME:
- *
- * Since this is a helper to implement @get_vblank_timestamp, we should
- * move it to &struct drm_crtc_helper_funcs, like all the other
- * helper-internal hooks.
+ * This is deprecated and should not be used by new drivers.
+ * Use &drm_crtc_helper_funcs.get_scanout_position instead.
*/
bool (*get_scanout_position) (struct drm_device *dev, unsigned int pipe,
bool in_vblank_irq, int *vpos, int *hpos,
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index 5a87f1bd7a3f..e398512bfd5f 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -450,6 +450,53 @@ struct drm_crtc_helper_funcs {
*/
void (*atomic_disable)(struct drm_crtc *crtc,
struct drm_crtc_state *old_crtc_state);
+
+ /**
+ * @get_scanout_position:
+ *
+ * Called by vblank timestamping code.
+ *
+ * Returns the current display scanout position from a CRTC and an
+ * optional accurate ktime_get() timestamp of when the position was
+ * measured. Note that this is a helper callback which is only used
+ * if a driver uses drm_calc_vbltimestamp_from_scanoutpos() for the
+ * @drm_driver.get_vblank_timestamp callback.
+ *
+ * Parameters:
+ *
+ * crtc:
+ * The CRTC.
+ * in_vblank_irq:
+ * True when called from drm_crtc_handle_vblank(). Some drivers
+ * need to apply some workarounds for gpu-specific vblank irq
+ * quirks if the flag is set.
+ * vpos:
+ * Target location for current vertical scanout position.
+ * hpos:
+ * Target location for current horizontal scanout position.
+ * stime:
+ * Target location for timestamp taken immediately before
+ * scanout position query. Can be NULL to skip timestamp.
+ * etime:
+ * Target location for timestamp taken immediately after
+ * scanout position query. Can be NULL to skip timestamp.
+ * mode:
+ * Current display timings.
+ *
+ * Returns vpos as a positive number while in active scanout area.
+ * Returns vpos as a negative number inside vblank, counting the number
+ * of scanlines to go until end of vblank, e.g., -1 means "one scanline
+ * until start of active scanout / end of vblank."
+ *
+ * Returns:
+ *
+ * True on success, false if a reliable scanout position counter could
+ * not be read out.
+ */
+ bool (*get_scanout_position)(struct drm_crtc *crtc,
+ bool in_vblank_irq, int *vpos, int *hpos,
+ ktime_t *stime, ktime_t *etime,
+ const struct drm_display_mode *mode);
};
/**
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
index c16c44052b3d..1c84e99b3f4f 100644
--- a/include/drm/drm_vblank.h
+++ b/include/drm/drm_vblank.h
@@ -238,4 +238,26 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,
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);
+
+typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
+ bool in_vblank_irq,
+ int *vpos, int *hpos,
+ ktime_t *stime, ktime_t *etime,
+ const struct drm_display_mode *mode);
+
+typedef bool (*drm_vblank_get_scanout_position_legacy_func)(struct drm_device *dev,
+ unsigned int pipe,
+ bool in_vblank_irq,
+ int *vpos, int *hpos,
+ ktime_t *stime, ktime_t *etime,
+ const struct drm_display_mode *mode);
+
+bool
+drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
+ int *max_error,
+ ktime_t *vblank_time,
+ bool in_vblank_irq,
+ drm_vblank_get_scanout_position_func get_scanout_position,
+ drm_vblank_get_scanout_position_legacy_func get_scanout_position_legacy);
+
#endif
--
2.24.1
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