diff options
Diffstat (limited to 'drivers/gpu/drm/drm_vblank.c')
| -rw-r--r-- | drivers/gpu/drm/drm_vblank.c | 268 |
1 files changed, 235 insertions, 33 deletions
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index cc3571e25a9a..5c14140cd0c2 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -131,13 +131,22 @@ * guaranteed to be enabled. * * On many hardware disabling the vblank interrupt cannot be done in a race-free - * manner, see &drm_driver.vblank_disable_immediate and + * manner, see &drm_vblank_crtc_config.disable_immediate and * &drm_driver.max_vblank_count. In that case the vblank core only disables the * vblanks after a timer has expired, which can be configured through the * ``vblankoffdelay`` module parameter. * - * Drivers for hardware without support for vertical-blanking interrupts - * must not call drm_vblank_init(). For such drivers, atomic helpers will + * Drivers for hardware without support for vertical-blanking interrupts can + * use DRM vblank timers to send vblank events at the rate of the current + * display mode's refresh. While not synchronized to the hardware's + * vertical-blanking regions, the timer helps DRM clients and compositors to + * adapt their update cycle to the display output. Drivers should set up + * vblanking as usual, but call drm_crtc_vblank_start_timer() and + * drm_crtc_vblank_cancel_timer() as part of their atomic mode setting. + * See also DRM vblank helpers for more information. + * + * Drivers without support for vertical-blanking interrupts nor timers must + * not call drm_vblank_init(). For these drivers, atomic helpers will * automatically generate fake vblank events as part of the display update. * This functionality also can be controlled by the driver by enabling and * disabling struct drm_crtc_state.no_vblank. @@ -487,7 +496,8 @@ out: static void vblank_disable_fn(struct timer_list *t) { - struct drm_vblank_crtc *vblank = from_timer(vblank, t, disable_timer); + struct drm_vblank_crtc *vblank = timer_container_of(vblank, t, + disable_timer); struct drm_device *dev = vblank->dev; unsigned int pipe = vblank->pipe; unsigned long irqflags; @@ -507,8 +517,11 @@ static void drm_vblank_init_release(struct drm_device *dev, void *ptr) drm_WARN_ON(dev, READ_ONCE(vblank->enabled) && drm_core_check_feature(dev, DRIVER_MODESET)); + if (vblank->vblank_timer.crtc) + hrtimer_cancel(&vblank->vblank_timer.timer); + drm_vblank_destroy_worker(vblank); - del_timer_sync(&vblank->disable_timer); + timer_delete_sync(&vblank->disable_timer); } /** @@ -686,7 +699,6 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants); * drm_atomic_helper_calc_timestamping_constants(). * * Returns: - * * Returns true on success, and false on failure, i.e. when no accurate * timestamp could be acquired. */ @@ -794,10 +806,8 @@ drm_crtc_vblank_helper_get_vblank_timestamp_internal( ts_vblank_time = ktime_to_timespec64(*vblank_time); drm_dbg_vbl(dev, - "crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n", - pipe, hpos, vpos, - (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000, - (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000, + "crtc %u : v p(%d,%d)@ %ptSp -> %ptSp [e %d us, %d rep]\n", + pipe, hpos, vpos, &ts_etime, &ts_vblank_time, duration_ns / 1000, i); return true; @@ -831,7 +841,6 @@ EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal); * drm_atomic_helper_calc_timestamping_constants(). * * Returns: - * * Returns true on success, and false on failure, i.e. when no accurate * timestamp could be acquired. */ @@ -1241,6 +1250,7 @@ EXPORT_SYMBOL(drm_crtc_vblank_get); void drm_vblank_put(struct drm_device *dev, unsigned int pipe) { struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); + int vblank_offdelay = vblank->config.offdelay_ms; if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) return; @@ -1250,13 +1260,13 @@ void drm_vblank_put(struct drm_device *dev, unsigned int pipe) /* Last user schedules interrupt disable */ if (atomic_dec_and_test(&vblank->refcount)) { - if (drm_vblank_offdelay == 0) + if (!vblank_offdelay) return; - else if (drm_vblank_offdelay < 0) + else if (vblank_offdelay < 0) vblank_disable_fn(&vblank->disable_timer); - else if (!dev->vblank_disable_immediate) + else if (!vblank->config.disable_immediate) mod_timer(&vblank->disable_timer, - jiffies + ((drm_vblank_offdelay * HZ)/1000)); + jiffies + ((vblank_offdelay * HZ) / 1000)); } } @@ -1265,7 +1275,8 @@ void drm_vblank_put(struct drm_device *dev, unsigned int pipe) * @crtc: which counter to give up * * Release ownership of a given vblank counter, turning off interrupts - * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. + * if possible. Disable interrupts after &drm_vblank_crtc_config.offdelay_ms + * milliseconds. */ void drm_crtc_vblank_put(struct drm_crtc *crtc) { @@ -1302,7 +1313,7 @@ void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe) ret = wait_event_timeout(vblank->queue, last != drm_vblank_count(dev, pipe), - msecs_to_jiffies(100)); + msecs_to_jiffies(1000)); drm_WARN(dev, ret == 0, "vblank wait timed out on crtc %i\n", pipe); @@ -1466,16 +1477,20 @@ void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc, EXPORT_SYMBOL(drm_crtc_set_max_vblank_count); /** - * drm_crtc_vblank_on - enable vblank events on a CRTC + * drm_crtc_vblank_on_config - enable vblank events on a CRTC with custom + * configuration options * @crtc: CRTC in question + * @config: Vblank configuration value * - * This functions restores the vblank interrupt state captured with - * drm_crtc_vblank_off() again and is generally called when enabling @crtc. Note - * that calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() can be - * unbalanced and so can also be unconditionally called in driver load code to - * reflect the current hardware state of the crtc. + * See drm_crtc_vblank_on(). In addition, this function allows you to provide a + * custom vblank configuration for a given CRTC. + * + * Note that @config is copied, the pointer does not need to stay valid beyond + * this function call. For details of the parameters see + * struct drm_vblank_crtc_config. */ -void drm_crtc_vblank_on(struct drm_crtc *crtc) +void drm_crtc_vblank_on_config(struct drm_crtc *crtc, + const struct drm_vblank_crtc_config *config) { struct drm_device *dev = crtc->dev; unsigned int pipe = drm_crtc_index(crtc); @@ -1488,6 +1503,8 @@ void drm_crtc_vblank_on(struct drm_crtc *crtc) drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n", pipe, vblank->enabled, vblank->inmodeset); + vblank->config = *config; + /* Drop our private "prevent drm_vblank_get" refcount */ if (vblank->inmodeset) { atomic_dec(&vblank->refcount); @@ -1500,10 +1517,33 @@ void drm_crtc_vblank_on(struct drm_crtc *crtc) * re-enable interrupts if there are users left, or the * user wishes vblank interrupts to be enabled all the time. */ - if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0) + if (atomic_read(&vblank->refcount) != 0 || !vblank->config.offdelay_ms) drm_WARN_ON(dev, drm_vblank_enable(dev, pipe)); spin_unlock_irq(&dev->vbl_lock); } +EXPORT_SYMBOL(drm_crtc_vblank_on_config); + +/** + * drm_crtc_vblank_on - enable vblank events on a CRTC + * @crtc: CRTC in question + * + * This functions restores the vblank interrupt state captured with + * drm_crtc_vblank_off() again and is generally called when enabling @crtc. Note + * that calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() can be + * unbalanced and so can also be unconditionally called in driver load code to + * reflect the current hardware state of the crtc. + * + * Note that unlike in drm_crtc_vblank_on_config(), default values are used. + */ +void drm_crtc_vblank_on(struct drm_crtc *crtc) +{ + const struct drm_vblank_crtc_config config = { + .offdelay_ms = drm_vblank_offdelay, + .disable_immediate = crtc->dev->vblank_disable_immediate + }; + + drm_crtc_vblank_on_config(crtc, &config); +} EXPORT_SYMBOL(drm_crtc_vblank_on); static void drm_vblank_restore(struct drm_device *dev, unsigned int pipe) @@ -1556,16 +1596,21 @@ static void drm_vblank_restore(struct drm_device *dev, unsigned int pipe) * * Note that drivers must have race-free high-precision timestamping support, * i.e. &drm_crtc_funcs.get_vblank_timestamp must be hooked up and - * &drm_driver.vblank_disable_immediate must be set to indicate the + * &drm_vblank_crtc_config.disable_immediate must be set to indicate the * time-stamping functions are race-free against vblank hardware counter * increments. */ void drm_crtc_vblank_restore(struct drm_crtc *crtc) { - WARN_ON_ONCE(!crtc->funcs->get_vblank_timestamp); - WARN_ON_ONCE(!crtc->dev->vblank_disable_immediate); + struct drm_device *dev = crtc->dev; + unsigned int pipe = drm_crtc_index(crtc); + struct drm_vblank_crtc *vblank = drm_vblank_crtc(dev, pipe); + + drm_WARN_ON_ONCE(dev, !crtc->funcs->get_vblank_timestamp); + drm_WARN_ON_ONCE(dev, vblank->inmodeset); + drm_WARN_ON_ONCE(dev, !vblank->config.disable_immediate); - drm_vblank_restore(crtc->dev, drm_crtc_index(crtc)); + drm_vblank_restore(dev, pipe); } EXPORT_SYMBOL(drm_crtc_vblank_restore); @@ -1754,7 +1799,7 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, /* If the counter is currently enabled and accurate, short-circuit * queries to return the cached timestamp of the last vblank. */ - if (dev->vblank_disable_immediate && + if (vblank->config.disable_immediate && drm_wait_vblank_is_query(vblwait) && READ_ONCE(vblank->enabled)) { drm_wait_vblank_reply(dev, pipe, &vblwait->reply); @@ -1918,8 +1963,8 @@ bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe) * been signaled. The disable has to be last (after * drm_handle_vblank_events) so that the timestamp is always accurate. */ - disable_irq = (dev->vblank_disable_immediate && - drm_vblank_offdelay > 0 && + disable_irq = (vblank->config.disable_immediate && + vblank->config.offdelay_ms > 0 && !atomic_read(&vblank->refcount)); drm_handle_vblank_events(dev, pipe); @@ -1992,7 +2037,8 @@ int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data, pipe = drm_crtc_index(crtc); vblank = drm_crtc_vblank_crtc(crtc); - vblank_enabled = dev->vblank_disable_immediate && READ_ONCE(vblank->enabled); + vblank_enabled = READ_ONCE(vblank->config.disable_immediate) && + READ_ONCE(vblank->enabled); if (!vblank_enabled) { ret = drm_crtc_vblank_get(crtc); @@ -2126,3 +2172,159 @@ err_free: return ret; } +/* + * VBLANK timer + */ + +static enum hrtimer_restart drm_vblank_timer_function(struct hrtimer *timer) +{ + struct drm_vblank_crtc_timer *vtimer = + container_of(timer, struct drm_vblank_crtc_timer, timer); + struct drm_crtc *crtc = vtimer->crtc; + const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private; + struct drm_device *dev = crtc->dev; + unsigned long flags; + ktime_t interval; + u64 ret_overrun; + bool succ; + + spin_lock_irqsave(&vtimer->interval_lock, flags); + interval = vtimer->interval; + spin_unlock_irqrestore(&vtimer->interval_lock, flags); + + if (!interval) + return HRTIMER_NORESTART; + + ret_overrun = hrtimer_forward_now(&vtimer->timer, interval); + if (ret_overrun != 1) + drm_dbg_vbl(dev, "vblank timer overrun\n"); + + if (crtc_funcs->handle_vblank_timeout) + succ = crtc_funcs->handle_vblank_timeout(crtc); + else + succ = drm_crtc_handle_vblank(crtc); + if (!succ) + return HRTIMER_NORESTART; + + return HRTIMER_RESTART; +} + +/** + * drm_crtc_vblank_start_timer - Starts the vblank timer on the given CRTC + * @crtc: the CRTC + * + * Drivers should call this function from their CRTC's enable_vblank + * function to start a vblank timer. The timer will fire after the duration + * of a full frame. drm_crtc_vblank_cancel_timer() disables a running timer. + * + * Returns: + * 0 on success, or a negative errno code otherwise. + */ +int drm_crtc_vblank_start_timer(struct drm_crtc *crtc) +{ + struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); + struct drm_vblank_crtc_timer *vtimer = &vblank->vblank_timer; + unsigned long flags; + + if (!vtimer->crtc) { + /* + * Set up the data structures on the first invocation. + */ + vtimer->crtc = crtc; + spin_lock_init(&vtimer->interval_lock); + hrtimer_setup(&vtimer->timer, drm_vblank_timer_function, + CLOCK_MONOTONIC, HRTIMER_MODE_REL); + } else { + /* + * Timer should not be active. If it is, wait for the + * previous cancel operations to finish. + */ + while (hrtimer_active(&vtimer->timer)) + hrtimer_try_to_cancel(&vtimer->timer); + } + + drm_calc_timestamping_constants(crtc, &crtc->mode); + + spin_lock_irqsave(&vtimer->interval_lock, flags); + vtimer->interval = ns_to_ktime(vblank->framedur_ns); + spin_unlock_irqrestore(&vtimer->interval_lock, flags); + + hrtimer_start(&vtimer->timer, vtimer->interval, HRTIMER_MODE_REL); + + return 0; +} +EXPORT_SYMBOL(drm_crtc_vblank_start_timer); + +/** + * drm_crtc_vblank_cancel_timer - Cancels the given CRTC's vblank timer + * @crtc: the CRTC + * + * Drivers should call this function from their CRTC's disable_vblank + * function to stop a vblank timer. + */ +void drm_crtc_vblank_cancel_timer(struct drm_crtc *crtc) +{ + struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); + struct drm_vblank_crtc_timer *vtimer = &vblank->vblank_timer; + unsigned long flags; + + /* + * Calling hrtimer_cancel() can result in a deadlock with DRM's + * vblank_time_lime_lock and hrtimers' softirq_expiry_lock. So + * clear interval and indicate cancellation. The timer function + * will cancel itself on the next invocation. + */ + + spin_lock_irqsave(&vtimer->interval_lock, flags); + vtimer->interval = 0; + spin_unlock_irqrestore(&vtimer->interval_lock, flags); + + hrtimer_try_to_cancel(&vtimer->timer); +} +EXPORT_SYMBOL(drm_crtc_vblank_cancel_timer); + +/** + * drm_crtc_vblank_get_vblank_timeout - Returns the vblank timeout + * @crtc: The CRTC + * @vblank_time: Returns the next vblank timestamp + * + * The helper drm_crtc_vblank_get_vblank_timeout() returns the next vblank + * timestamp of the CRTC's vblank timer according to the timer's expiry + * time. + */ +void drm_crtc_vblank_get_vblank_timeout(struct drm_crtc *crtc, ktime_t *vblank_time) +{ + struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc); + struct drm_vblank_crtc_timer *vtimer = &vblank->vblank_timer; + u64 cur_count; + ktime_t cur_time; + + if (!READ_ONCE(vblank->enabled)) { + *vblank_time = ktime_get(); + return; + } + + /* + * A concurrent vblank timeout could update the expires field before + * we compare it with the vblank time. Hence we'd compare the old + * expiry time to the new vblank time; deducing the timer had already + * expired. Reread until we get consistent values from both fields. + */ + do { + cur_count = drm_crtc_vblank_count_and_time(crtc, &cur_time); + *vblank_time = READ_ONCE(vtimer->timer.node.expires); + } while (cur_count != drm_crtc_vblank_count_and_time(crtc, &cur_time)); + + if (drm_WARN_ON(crtc->dev, !ktime_compare(*vblank_time, cur_time))) + return; /* Already expired */ + + /* + * To prevent races we roll the hrtimer forward before we do any + * interrupt processing - this is how real hw works (the interrupt + * is only generated after all the vblank registers are updated) + * and what the vblank core expects. Therefore we need to always + * correct the timestamp by one frame. + */ + *vblank_time = ktime_sub(*vblank_time, vtimer->interval); +} +EXPORT_SYMBOL(drm_crtc_vblank_get_vblank_timeout); |