diff options
Diffstat (limited to 'drivers/gpu/drm/drm_irq.c')
| -rw-r--r-- | drivers/gpu/drm/drm_irq.c | 563 |
1 files changed, 538 insertions, 25 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 722700d5d73e..77c875db5aae 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -40,6 +40,22 @@ #include <linux/slab.h> #include <linux/vgaarb.h> + +/* Access macro for slots in vblank timestamp ringbuffer. */ +#define vblanktimestamp(dev, crtc, count) ( \ + (dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \ + ((count) % DRM_VBLANKTIME_RBSIZE)]) + +/* Retry timestamp calculation up to 3 times to satisfy + * drm_timestamp_precision before giving up. + */ +#define DRM_TIMESTAMP_MAXRETRIES 3 + +/* Threshold in nanoseconds for detection of redundant + * vblank irq in drm_handle_vblank(). 1 msec should be ok. + */ +#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000 + /** * Get interrupt from bus id. * @@ -77,6 +93,87 @@ int drm_irq_by_busid(struct drm_device *dev, void *data, return 0; } +/* + * Clear vblank timestamp buffer for a crtc. + */ +static void clear_vblank_timestamps(struct drm_device *dev, int crtc) +{ + memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0, + DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval)); +} + +/* + * Disable vblank irq's on crtc, make sure that last vblank count + * of hardware and corresponding consistent software vblank counter + * are preserved, even if there are any spurious vblank irq's after + * disable. + */ +static void vblank_disable_and_save(struct drm_device *dev, int crtc) +{ + unsigned long irqflags; + u32 vblcount; + s64 diff_ns; + int vblrc; + struct timeval tvblank; + + /* Prevent vblank irq processing while disabling vblank irqs, + * so no updates of timestamps or count can happen after we've + * disabled. Needed to prevent races in case of delayed irq's. + * Disable preemption, so vblank_time_lock is held as short as + * possible, even under a kernel with PREEMPT_RT patches. + */ + preempt_disable(); + spin_lock_irqsave(&dev->vblank_time_lock, irqflags); + + dev->driver->disable_vblank(dev, crtc); + dev->vblank_enabled[crtc] = 0; + + /* No further vblank irq's will be processed after + * this point. Get current hardware vblank count and + * vblank timestamp, repeat until they are consistent. + * + * FIXME: There is still a race condition here and in + * drm_update_vblank_count() which can cause off-by-one + * reinitialization of software vblank counter. If gpu + * vblank counter doesn't increment exactly at the leading + * edge of a vblank interval, then we can lose 1 count if + * we happen to execute between start of vblank and the + * delayed gpu counter increment. + */ + do { + dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc); + vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); + } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc)); + + /* Compute time difference to stored timestamp of last vblank + * as updated by last invocation of drm_handle_vblank() in vblank irq. + */ + vblcount = atomic_read(&dev->_vblank_count[crtc]); + diff_ns = timeval_to_ns(&tvblank) - + timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); + + /* If there is at least 1 msec difference between the last stored + * timestamp and tvblank, then we are currently executing our + * disable inside a new vblank interval, the tvblank timestamp + * corresponds to this new vblank interval and the irq handler + * for this vblank didn't run yet and won't run due to our disable. + * Therefore we need to do the job of drm_handle_vblank() and + * increment the vblank counter by one to account for this vblank. + * + * Skip this step if there isn't any high precision timestamp + * available. In that case we can't account for this and just + * hope for the best. + */ + if ((vblrc > 0) && (abs(diff_ns) > 1000000)) + atomic_inc(&dev->_vblank_count[crtc]); + + /* Invalidate all timestamps while vblank irq's are off. */ + clear_vblank_timestamps(dev, crtc); + + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); + preempt_enable(); +} + static void vblank_disable_fn(unsigned long arg) { struct drm_device *dev = (struct drm_device *)arg; @@ -91,10 +188,7 @@ static void vblank_disable_fn(unsigned long arg) if (atomic_read(&dev->vblank_refcount[i]) == 0 && dev->vblank_enabled[i]) { DRM_DEBUG("disabling vblank on crtc %d\n", i); - dev->last_vblank[i] = - dev->driver->get_vblank_counter(dev, i); - dev->driver->disable_vblank(dev, i); - dev->vblank_enabled[i] = 0; + vblank_disable_and_save(dev, i); } spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } @@ -117,6 +211,7 @@ void drm_vblank_cleanup(struct drm_device *dev) kfree(dev->last_vblank); kfree(dev->last_vblank_wait); kfree(dev->vblank_inmodeset); + kfree(dev->_vblank_time); dev->num_crtcs = 0; } @@ -129,6 +224,8 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs) setup_timer(&dev->vblank_disable_timer, vblank_disable_fn, (unsigned long)dev); spin_lock_init(&dev->vbl_lock); + spin_lock_init(&dev->vblank_time_lock); + dev->num_crtcs = num_crtcs; dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs, @@ -161,6 +258,19 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs) if (!dev->vblank_inmodeset) goto err; + dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE, + sizeof(struct timeval), GFP_KERNEL); + if (!dev->_vblank_time) + goto err; + + DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n"); + + /* Driver specific high-precision vblank timestamping supported? */ + if (dev->driver->get_vblank_timestamp) + DRM_INFO("Driver supports precise vblank timestamp query.\n"); + else + DRM_INFO("No driver support for vblank timestamp query.\n"); + /* Zero per-crtc vblank stuff */ for (i = 0; i < num_crtcs; i++) { init_waitqueue_head(&dev->vbl_queue[i]); @@ -279,7 +389,7 @@ EXPORT_SYMBOL(drm_irq_install); * * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq. */ -int drm_irq_uninstall(struct drm_device * dev) +int drm_irq_uninstall(struct drm_device *dev) { unsigned long irqflags; int irq_enabled, i; @@ -335,7 +445,9 @@ int drm_control(struct drm_device *dev, void *data, { struct drm_control *ctl = data; - /* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */ + /* if we haven't irq we fallback for compatibility reasons - + * this used to be a separate function in drm_dma.h + */ switch (ctl->func) { @@ -360,6 +472,287 @@ int drm_control(struct drm_device *dev, void *data, } /** + * drm_calc_timestamping_constants - 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. + * + * @crtc drm_crtc whose timestamp constants should be updated. + * + */ +void drm_calc_timestamping_constants(struct drm_crtc *crtc) +{ + s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0; + u64 dotclock; + + /* Dot clock in Hz: */ + dotclock = (u64) crtc->hwmode.clock * 1000; + + /* Valid dotclock? */ + if (dotclock > 0) { + /* Convert scanline length in pixels and video dot clock to + * line duration, frame duration and pixel duration in + * nanoseconds: + */ + pixeldur_ns = (s64) div64_u64(1000000000, dotclock); + linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal * + 1000000000), dotclock); + framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns; + } else + DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n", + crtc->base.id); + + crtc->pixeldur_ns = pixeldur_ns; + crtc->linedur_ns = linedur_ns; + crtc->framedur_ns = framedur_ns; + + DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n", + crtc->base.id, crtc->hwmode.crtc_htotal, + crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay); + DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n", + crtc->base.id, (int) dotclock/1000, (int) framedur_ns, + (int) linedur_ns, (int) pixeldur_ns); +} +EXPORT_SYMBOL(drm_calc_timestamping_constants); + +/** + * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms + * drivers. Implements calculation of exact vblank timestamps from + * given drm_display_mode timings and current video scanout position + * of a crtc. This can be called from within get_vblank_timestamp() + * implementation of a kms driver to implement the actual timestamping. + * + * Should return timestamps conforming to the OML_sync_control OpenML + * extension specification. The timestamp corresponds to the end of + * the vblank interval, aka start of scanout of topmost-leftmost display + * pixel in the following video frame. + * + * Requires support for optional dev->driver->get_scanout_position() + * in kms driver, plus a bit of setup code to provide a drm_display_mode + * that corresponds to the true scanout timing. + * + * The current implementation only handles standard video modes. It + * returns as no operation if a doublescan or interlaced video mode is + * active. Higher level code is expected to handle this. + * + * @dev: DRM device. + * @crtc: Which crtc's 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 struct timeval which should receive the timestamp. + * @flags: Flags to pass to driver: + * 0 = Default. + * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. + * @refcrtc: drm_crtc* of crtc which defines scanout timing. + * + * Returns negative value on error, failure or if not supported in current + * video mode: + * + * -EINVAL - Invalid crtc. + * -EAGAIN - Temporary unavailable, e.g., called before initial modeset. + * -ENOTSUPP - Function not supported in current display mode. + * -EIO - Failed, e.g., due to failed scanout position query. + * + * Returns or'ed positive status flags on success: + * + * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping. + * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval. + * + */ +int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, + int *max_error, + struct timeval *vblank_time, + unsigned flags, + struct drm_crtc *refcrtc) +{ + struct timeval stime, raw_time; + struct drm_display_mode *mode; + int vbl_status, vtotal, vdisplay; + int vpos, hpos, i; + s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns; + bool invbl; + + if (crtc < 0 || crtc >= dev->num_crtcs) { + DRM_ERROR("Invalid crtc %d\n", crtc); + return -EINVAL; + } + + /* 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"); + return -EIO; + } + + mode = &refcrtc->hwmode; + vtotal = mode->crtc_vtotal; + vdisplay = mode->crtc_vdisplay; + + /* Durations of frames, lines, pixels in nanoseconds. */ + framedur_ns = refcrtc->framedur_ns; + linedur_ns = refcrtc->linedur_ns; + pixeldur_ns = refcrtc->pixeldur_ns; + + /* If mode timing undefined, just return as no-op: + * Happens during initial modesetting of a crtc. + */ + if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) { + DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc); + return -EAGAIN; + } + + /* Don't know yet how to handle interlaced or + * double scan modes. Just no-op for now. + */ + if (mode->flags & (DRM_MODE_FLAG_INTERLACE | DRM_MODE_FLAG_DBLSCAN)) { + DRM_DEBUG("crtc %d: Noop due to unsupported mode.\n", crtc); + return -ENOTSUPP; + } + + /* Get current scanout position with system timestamp. + * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times + * if single query takes longer than max_error nanoseconds. + * + * This guarantees a tight bound on maximum error if + * code gets preempted or delayed for some reason. + */ + for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { + /* Disable preemption to make it very likely to + * succeed in the first iteration even on PREEMPT_RT kernel. + */ + preempt_disable(); + + /* Get system timestamp before query. */ + do_gettimeofday(&stime); + + /* Get vertical and horizontal scanout pos. vpos, hpos. */ + vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos); + + /* Get system timestamp after query. */ + do_gettimeofday(&raw_time); + + preempt_enable(); + + /* Return as no-op if scanout query unsupported or failed. */ + if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { + DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n", + crtc, vbl_status); + return -EIO; + } + + duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime); + + /* Accept result with < max_error nsecs timing uncertainty. */ + if (duration_ns <= (s64) *max_error) + break; + } + + /* Noisy system timing? */ + if (i == DRM_TIMESTAMP_MAXRETRIES) { + DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n", + crtc, (int) duration_ns/1000, *max_error/1000, i); + } + + /* Return upper bound of timestamp precision error. */ + *max_error = (int) duration_ns; + + /* Check if in vblank area: + * vpos is >=0 in video scanout area, but negative + * within vblank area, counting down the number of lines until + * start of scanout. + */ + invbl = vbl_status & DRM_SCANOUTPOS_INVBL; + + /* Convert scanout position into elapsed time at raw_time query + * since start of scanout at first display scanline. delta_ns + * can be negative if start of scanout hasn't happened yet. + */ + delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns; + + /* Is vpos outside nominal vblank area, but less than + * 1/100 of a frame height away from start of vblank? + * If so, assume this isn't a massively delayed vblank + * interrupt, but a vblank interrupt that fired a few + * microseconds before true start of vblank. Compensate + * by adding a full frame duration to the final timestamp. + * Happens, e.g., on ATI R500, R600. + * + * We only do this if DRM_CALLED_FROM_VBLIRQ. + */ + if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl && + ((vdisplay - vpos) < vtotal / 100)) { + delta_ns = delta_ns - framedur_ns; + + /* Signal this correction as "applied". */ + vbl_status |= 0x8; + } + + /* Subtract time delta from raw timestamp to get final + * vblank_time timestamp for end of vblank. + */ + *vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns); + + DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %d.%d -> %d.%d [e %d us, %d rep]\n", + crtc, (int) vbl_status, hpos, vpos, raw_time.tv_sec, + raw_time.tv_usec, vblank_time->tv_sec, vblank_time->tv_usec, + (int) duration_ns/1000, i); + + vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD; + if (invbl) + vbl_status |= DRM_VBLANKTIME_INVBL; + + return vbl_status; +} +EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos); + +/** + * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent + * vblank interval. + * + * @dev: DRM device + * @crtc: which crtc's vblank timestamp to retrieve + * @tvblank: Pointer to target struct timeval which should receive the timestamp + * @flags: Flags to pass to driver: + * 0 = Default. + * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. + * + * Fetches the system timestamp corresponding to the time of the most recent + * vblank interval on specified crtc. May call into kms-driver to + * compute the timestamp with a high-precision GPU specific method. + * + * Returns zero if timestamp originates from uncorrected do_gettimeofday() + * call, i.e., it isn't very precisely locked to the true vblank. + * + * Returns non-zero if timestamp is considered to be very precise. + */ +u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, + struct timeval *tvblank, unsigned flags) +{ + int ret = 0; + + /* 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)) { + ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error, + tvblank, flags); + if (ret > 0) + return (u32) ret; + } + + /* GPU high precision timestamp query unsupported or failed. + * Return gettimeofday timestamp as best estimate. + */ + do_gettimeofday(tvblank); + + return 0; +} +EXPORT_SYMBOL(drm_get_last_vbltimestamp); + +/** * drm_vblank_count - retrieve "cooked" vblank counter value * @dev: DRM device * @crtc: which counter to retrieve @@ -375,6 +768,40 @@ u32 drm_vblank_count(struct drm_device *dev, int crtc) EXPORT_SYMBOL(drm_vblank_count); /** + * drm_vblank_count_and_time - retrieve "cooked" vblank counter value + * and the system timestamp corresponding to that vblank counter value. + * + * @dev: DRM device + * @crtc: which counter to retrieve + * @vblanktime: Pointer to struct timeval to receive the vblank timestamp. + * + * Fetches the "cooked" vblank count value that represents the number of + * vblank events since the system was booted, including lost events due to + * modesetting activity. Returns corresponding system timestamp of the time + * of the vblank interval that corresponds to the current value vblank counter + * value. + */ +u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, + struct timeval *vblanktime) +{ + u32 cur_vblank; + + /* Read timestamp from slot of _vblank_time ringbuffer + * that corresponds to current vblank count. Retry if + * count has incremented during readout. This works like + * a seqlock. + */ + do { + cur_vblank = atomic_read(&dev->_vblank_count[crtc]); + *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); + smp_rmb(); + } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc])); + + return cur_vblank; +} +EXPORT_SYMBOL(drm_vblank_count_and_time); + +/** * drm_update_vblank_count - update the master vblank counter * @dev: DRM device * @crtc: counter to update @@ -392,7 +819,8 @@ EXPORT_SYMBOL(drm_vblank_count); */ static void drm_update_vblank_count(struct drm_device *dev, int crtc) { - u32 cur_vblank, diff; + u32 cur_vblank, diff, tslot, rc; + struct timeval t_vblank; /* * Interrupts were disabled prior to this call, so deal with counter @@ -400,8 +828,18 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc) * NOTE! It's possible we lost a full dev->max_vblank_count events * here if the register is small or we had vblank interrupts off for * a long time. + * + * We repeat the hardware vblank counter & timestamp query until + * we get consistent results. This to prevent races between gpu + * updating its hardware counter while we are retrieving the + * corresponding vblank timestamp. */ - cur_vblank = dev->driver->get_vblank_counter(dev, crtc); + do { + cur_vblank = dev->driver->get_vblank_counter(dev, crtc); + rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0); + } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc)); + + /* Deal with counter wrap */ diff = cur_vblank - dev->last_vblank[crtc]; if (cur_vblank < dev->last_vblank[crtc]) { diff += dev->max_vblank_count; @@ -413,6 +851,16 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc) DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", crtc, diff); + /* Reinitialize corresponding vblank timestamp if high-precision query + * available. Skip this step if query unsupported or failed. Will + * reinitialize delayed at next vblank interrupt in that case. + */ + if (rc) { + tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; + vblanktimestamp(dev, crtc, tslot) = t_vblank; + smp_wmb(); + } + atomic_add(diff, &dev->_vblank_count[crtc]); } @@ -429,15 +877,27 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc) */ int drm_vblank_get(struct drm_device *dev, int crtc) { - unsigned long irqflags; + unsigned long irqflags, irqflags2; int ret = 0; spin_lock_irqsave(&dev->vbl_lock, irqflags); /* Going from 0->1 means we have to enable interrupts again */ if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) { + /* Disable preemption while holding vblank_time_lock. Do + * it explicitely to guard against PREEMPT_RT kernel. + */ + preempt_disable(); + spin_lock_irqsave(&dev->vblank_time_lock, irqflags2); if (!dev->vblank_enabled[crtc]) { + /* Enable vblank irqs under vblank_time_lock protection. + * All vblank count & timestamp updates are held off + * until we are done reinitializing master counter and + * timestamps. Filtercode in drm_handle_vblank() will + * prevent double-accounting of same vblank interval. + */ ret = dev->driver->enable_vblank(dev, crtc); - DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret); + DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", + crtc, ret); if (ret) atomic_dec(&dev->vblank_refcount[crtc]); else { @@ -445,6 +905,8 @@ int drm_vblank_get(struct drm_device *dev, int crtc) drm_update_vblank_count(dev, crtc); } } + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2); + preempt_enable(); } else { if (!dev->vblank_enabled[crtc]) { atomic_dec(&dev->vblank_refcount[crtc]); @@ -463,15 +925,17 @@ EXPORT_SYMBOL(drm_vblank_get); * @crtc: which counter to give up * * Release ownership of a given vblank counter, turning off interrupts - * if possible. + * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. */ void drm_vblank_put(struct drm_device *dev, int crtc) { - BUG_ON (atomic_read (&dev->vblank_refcount[crtc]) == 0); + BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0); /* Last user schedules interrupt disable */ - if (atomic_dec_and_test(&dev->vblank_refcount[crtc])) - mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ); + if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) && + (drm_vblank_offdelay > 0)) + mod_timer(&dev->vblank_disable_timer, + jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000)); } EXPORT_SYMBOL(drm_vblank_put); @@ -480,10 +944,8 @@ void drm_vblank_off(struct drm_device *dev, int crtc) unsigned long irqflags; spin_lock_irqsave(&dev->vbl_lock, irqflags); - dev->driver->disable_vblank(dev, crtc); + vblank_disable_and_save(dev, crtc); DRM_WAKEUP(&dev->vbl_queue[crtc]); - dev->vblank_enabled[crtc] = 0; - dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc); spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } EXPORT_SYMBOL(drm_vblank_off); @@ -602,7 +1064,6 @@ static int drm_queue_vblank_event(struct drm_device *dev, int pipe, e->base.file_priv = file_priv; e->base.destroy = (void (*) (struct drm_pending_event *)) kfree; - do_gettimeofday(&now); spin_lock_irqsave(&dev->event_lock, flags); if (file_priv->event_space < sizeof e->event) { @@ -611,7 +1072,8 @@ static int drm_queue_vblank_event(struct drm_device *dev, int pipe, } file_priv->event_space -= sizeof e->event; - seq = drm_vblank_count(dev, pipe); + seq = drm_vblank_count_and_time(dev, pipe, &now); + if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) && (seq - vblwait->request.sequence) <= (1 << 23)) { vblwait->request.sequence = seq + 1; @@ -727,11 +1189,10 @@ int drm_wait_vblank(struct drm_device *dev, void *data, if (ret != -EINTR) { struct timeval now; - do_gettimeofday(&now); - + vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now); vblwait->reply.tval_sec = now.tv_sec; vblwait->reply.tval_usec = now.tv_usec; - vblwait->reply.sequence = drm_vblank_count(dev, crtc); + DRM_DEBUG("returning %d to client\n", vblwait->reply.sequence); } else { @@ -750,8 +1211,7 @@ void drm_handle_vblank_events(struct drm_device *dev, int crtc) unsigned long flags; unsigned int seq; - do_gettimeofday(&now); - seq = drm_vblank_count(dev, crtc); + seq = drm_vblank_count_and_time(dev, crtc, &now); spin_lock_irqsave(&dev->event_lock, flags); @@ -789,11 +1249,64 @@ void drm_handle_vblank_events(struct drm_device *dev, int crtc) */ void drm_handle_vblank(struct drm_device *dev, int crtc) { + u32 vblcount; + s64 diff_ns; + struct timeval tvblank; + unsigned long irqflags; + if (!dev->num_crtcs) return; - atomic_inc(&dev->_vblank_count[crtc]); + /* Need timestamp lock to prevent concurrent execution with + * vblank enable/disable, as this would cause inconsistent + * or corrupted timestamps and vblank counts. + */ + spin_lock_irqsave(&dev->vblank_time_lock, irqflags); + + /* Vblank irq handling disabled. Nothing to do. */ + if (!dev->vblank_enabled[crtc]) { + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); + return; + } + + /* Fetch corresponding timestamp for this vblank interval from + * driver and store it in proper slot of timestamp ringbuffer. + */ + + /* Get current timestamp and count. */ + vblcount = atomic_read(&dev->_vblank_count[crtc]); + drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ); + + /* Compute time difference to timestamp of last vblank */ + diff_ns = timeval_to_ns(&tvblank) - + timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); + + /* Update vblank timestamp and count if at least + * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds + * difference between last stored timestamp and current + * timestamp. A smaller difference means basically + * identical timestamps. Happens if this vblank has + * been already processed and this is a redundant call, + * e.g., due to spurious vblank interrupts. We need to + * ignore those for accounting. + */ + if (abs(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { + /* Store new timestamp in ringbuffer. */ + vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; + smp_wmb(); + + /* Increment cooked vblank count. This also atomically commits + * the timestamp computed above. + */ + atomic_inc(&dev->_vblank_count[crtc]); + } else { + DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", + crtc, (int) diff_ns); + } + DRM_WAKEUP(&dev->vbl_queue[crtc]); drm_handle_vblank_events(dev, crtc); + + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); } EXPORT_SYMBOL(drm_handle_vblank); |
