The callback get_vblank_timestamp() is currently located in struct drm_driver, but really belongs into struct drm_crtc_funcs. Add an equivalent there. Driver will be converted in separate patches.
The default implementation is drm_calc_vbltimestamp_from_scanoutpos(). The patch adds drm_crtc_vblank_helper_get_vblank_timestamp(), which is an implementation for the CRTC callback.
v3: * use refactored timestamp calculation to minimize duplicated code * do more checks for crtc != NULL to support legacy drivers v2: * rename helper to drm_crtc_vblank_helper_get_vblank_timestamp() * replace drm_calc_vbltimestamp_from_scanoutpos() with drm_crtc_vblank_helper_get_vblank_timestamp() in docs
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de --- drivers/gpu/drm/drm_vblank.c | 74 +++++++++++++++++++++--- include/drm/drm_crtc.h | 46 ++++++++++++++- include/drm/drm_modeset_helper_vtables.h | 4 +- include/drm/drm_vblank.h | 16 +++-- 4 files changed, 123 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 7e962c29780c..fc297043e3ba 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -333,7 +333,9 @@ u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc) u64 vblank; unsigned long flags;
- WARN_ONCE(drm_debug_enabled(DRM_UT_VBL) && !dev->driver->get_vblank_timestamp, + WARN_ONCE(drm_debug_enabled(DRM_UT_VBL) && + !crtc->funcs->get_vblank_timestamp && + !dev->driver->get_vblank_timestamp, "This function requires support for accurate vblank timestamps.");
spin_lock_irqsave(&dev->vblank_time_lock, flags); @@ -511,9 +513,9 @@ EXPORT_SYMBOL(drm_crtc_vblank_waitqueue); * * Calculate and store various constants which are later needed by vblank and * swap-completion timestamping, e.g, by - * drm_calc_vbltimestamp_from_scanoutpos(). They are derived from CRTC's true - * scanout timing, so they take things like panel scaling or other adjustments - * into account. + * drm_crtc_vblank_helper_get_vblank_timestamp(). They are derived from + * CRTC's true scanout timing, so they take things like panel scaling or + * other adjustments into account. */ void drm_calc_timestamping_constants(struct drm_crtc *crtc, const struct drm_display_mode *mode) @@ -577,8 +579,9 @@ 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_crtc_helper_funcs.get_scanout_position is implemented. + * used as the &drm_crtc_funcs.get_vblank_timestamp implementation of a kms + * driver if &drm_crtc_helper_funcs.get_scanout_position or + * &drm_driver.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 @@ -774,6 +777,48 @@ drm_crtc_vblank_helper_get_vblank_timestamp_internal( } EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal);
+/** + * drm_crtc_vblank_helper_get_vblank_timestamp - precise vblank timestamp + * helper + * @crtc: 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. + * + * 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_crtc_funcs.get_vblank_timestamp implementation of a kms + * driver 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 + * (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(struct drm_crtc *crtc, + int *max_error, + ktime_t *vblank_time, + bool in_vblank_irq) +{ + return drm_crtc_vblank_helper_get_vblank_timestamp_internal( + crtc, max_error, vblank_time, in_vblank_irq, + crtc->helper_private->get_scanout_position, NULL); +} +EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp); + /** * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent * vblank interval @@ -799,15 +844,22 @@ static bool drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe, ktime_t *tvblank, bool in_vblank_irq) { + struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); bool ret = false;
/* Define requested maximum error on timestamps (nanoseconds). */ int max_error = (int) drm_timestamp_precision * 1000;
/* Query driver if possible and precision timestamping enabled. */ - if (dev->driver->get_vblank_timestamp && (max_error > 0)) + if (crtc && crtc->funcs->get_vblank_timestamp && max_error > 0) { + struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); + + ret = crtc->funcs->get_vblank_timestamp(crtc, &max_error, + tvblank, in_vblank_irq); + } else if (dev->driver->get_vblank_timestamp && max_error > 0) { ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error, tvblank, in_vblank_irq); + }
/* GPU high precision timestamp query unsupported or failed. * Return current monotonic/gettimeofday timestamp as best estimate. @@ -1790,9 +1842,11 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe) { + struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe); struct drm_pending_vblank_event *e, *t; ktime_t now; u64 seq; + bool high_prec;
assert_spin_locked(&dev->event_lock);
@@ -1812,8 +1866,10 @@ static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe) send_vblank_event(dev, e, seq, now); }
- trace_drm_vblank_event(pipe, seq, now, - dev->driver->get_vblank_timestamp != NULL); + high_prec = crtc && crtc->funcs->get_vblank_timestamp || + dev->driver->get_vblank_timestamp; + + trace_drm_vblank_event(pipe, seq, now, high_prec); }
/** diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 5e9b15a0e8c5..db46abbbf4e7 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -867,6 +867,47 @@ struct drm_crtc_funcs { * new drivers as the replacement of &drm_driver.disable_vblank hook. */ void (*disable_vblank)(struct drm_crtc *crtc); + + /** + * @get_vblank_timestamp: + * + * Called by drm_get_last_vbltimestamp(). Should return a precise + * timestamp when the most recent vblank interval ended or will end. + * + * Specifically, the timestamp in @vblank_time should correspond as + * closely as possible to the time when the first video scanline of + * the video frame after the end of vblank will start scanning out, + * the time immediately after end of the vblank interval. If the + * @crtc is currently inside vblank, this will be a time in the future. + * If the @crtc is currently scanning out a frame, this will be the + * past start time of the current scanout. This is meant to adhere + * to the OpenML OML_sync_control extension specification. + * + * Parameters: + * + * crtc: + * CRTC for which timestamp should be returned. + * max_error: + * Maximum allowable timestamp error in nanoseconds. + * Implementation should strive to provide timestamp + * with an error of at most max_error nanoseconds. + * Returns true upper bound on error for timestamp. + * vblank_time: + * Target location for returned vblank 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. + * + * Returns: + * + * True on success, false on failure, which means the core should + * fallback to a simple timestamp taken in drm_crtc_handle_vblank(). + */ + bool (*get_vblank_timestamp)(struct drm_crtc *crtc, + int *max_error, + ktime_t *vblank_time, + bool in_vblank_irq); };
/** @@ -974,11 +1015,12 @@ struct drm_crtc { * Programmed mode in hw, after adjustments for encoders, crtc, panel * scaling etc. Should only be used by legacy drivers, for high * precision vblank timestamps in - * drm_calc_vbltimestamp_from_scanoutpos(). + * drm_crtc_vblank_helper_get_vblank_timestamp(). * * Note that atomic drivers should not use this, but instead use * &drm_crtc_state.adjusted_mode. And for high-precision timestamps - * drm_calc_vbltimestamp_from_scanoutpos() used &drm_vblank_crtc.hwmode, + * drm_crtc_vblank_helper_get_vblank_timestamp() used + * &drm_vblank_crtc.hwmode, * which is filled out by calling drm_calc_timestamping_constants(). */ struct drm_display_mode hwmode; diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index e398512bfd5f..0afaf58da40d 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -459,8 +459,8 @@ struct drm_crtc_helper_funcs { * 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. + * if a driver uses drm_crtc_vblank_helper_get_vblank_timestamp() + * for the @drm_crtc_funcs.get_vblank_timestamp callback. * * Parameters: * diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h index 1c84e99b3f4f..4bfffe990828 100644 --- a/include/drm/drm_vblank.h +++ b/include/drm/drm_vblank.h @@ -174,13 +174,13 @@ struct drm_vblank_crtc { unsigned int pipe; /** * @framedur_ns: Frame/Field duration in ns, used by - * drm_calc_vbltimestamp_from_scanoutpos() and computed by + * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by * drm_calc_timestamping_constants(). */ int framedur_ns; /** * @linedur_ns: Line duration in ns, used by - * drm_calc_vbltimestamp_from_scanoutpos() and computed by + * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by * drm_calc_timestamping_constants(). */ int linedur_ns; @@ -190,8 +190,8 @@ struct drm_vblank_crtc { * * Cache of the current hardware display mode. Only valid when @enabled * is set. This is used by helpers like - * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the - * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode, + * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access + * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode, * because that one is really hard to get from interrupt context. */ struct drm_display_mode hwmode; @@ -239,6 +239,10 @@ 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);
+/* + * Helpers for struct drm_crtc_funcs + */ + typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc, bool in_vblank_irq, int *vpos, int *hpos, @@ -259,5 +263,9 @@ drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc, bool in_vblank_irq, drm_vblank_get_scanout_position_func get_scanout_position, drm_vblank_get_scanout_position_legacy_func get_scanout_position_legacy); +bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc, + int *max_error, + ktime_t *vblank_time, + bool in_vblank_irq);
#endif