From 78c6e170badd22c86a5b50a7eb038a02024b8f03 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 31 Jan 2011 10:48:04 +0000 Subject: drm/i915: Suppress spurious vblank interrupts Hugh Dickins found that characters in xterm were going missing and oft delayed. Being the curious type, he managed to associate this with the new high-precision vblank patches; disabling these he found, restored the orderliness of his characters. The oddness begins when one realised that Hugh was not using vblanks at all on his system (fvwm and some xterms). Instead, all he had to go on were warning of a pipe underrun, curiously enough at around 60Hz. He poked and found that in addition to the underrun warning, the hardware was flagging the start of a new frame, a vblank, which in turn was kicking off the pending vblank processing code. There is little we can do for the underruns on Hugh's machine, a Crestline [965GM], which must have its FIFO watermarks set to 8. However, we do not need to process the vblank if we know that they are disabled... Reported-by: Hugh Dickins Signed-off-by: Chris Wilson --- drivers/gpu/drm/drm_irq.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 0054e957203f..3dadfa2a8528 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1250,7 +1250,7 @@ void drm_handle_vblank_events(struct drm_device *dev, int crtc) * Drivers should call this routine in their vblank interrupt handlers to * update the vblank counter and send any signals that may be pending. */ -void drm_handle_vblank(struct drm_device *dev, int crtc) +bool drm_handle_vblank(struct drm_device *dev, int crtc) { u32 vblcount; s64 diff_ns; @@ -1258,7 +1258,7 @@ void drm_handle_vblank(struct drm_device *dev, int crtc) unsigned long irqflags; if (!dev->num_crtcs) - return; + return false; /* Need timestamp lock to prevent concurrent execution with * vblank enable/disable, as this would cause inconsistent @@ -1269,7 +1269,7 @@ void drm_handle_vblank(struct drm_device *dev, int crtc) /* Vblank irq handling disabled. Nothing to do. */ if (!dev->vblank_enabled[crtc]) { spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); - return; + return false; } /* Fetch corresponding timestamp for this vblank interval from @@ -1311,5 +1311,6 @@ void drm_handle_vblank(struct drm_device *dev, int crtc) drm_handle_vblank_events(dev, crtc); spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); + return true; } EXPORT_SYMBOL(drm_handle_vblank); -- cgit v1.2.3 From c4cc383915549cf14f027f374904e30c13653dac Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Mon, 21 Feb 2011 05:42:00 +0100 Subject: drm/vblank: Use abs64(diff_ns) for s64 diff_ns instead of abs(diff_ns) Use of abs() wrongly wrapped diff_ns to 32 bit, which gives a 1/4000 probability of a missed vblank increment at each vblank irq reenable if the kms driver doesn't support high precision vblank timestamping. Not a big deal in practice, but let's make it nice. Signed-off-by: Mario Kleiner Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 3dadfa2a8528..6d2d4faf8678 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,7 +164,7 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc) * available. In that case we can't account for this and just * hope for the best. */ - if ((vblrc > 0) && (abs(diff_ns) > 1000000)) + if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) atomic_inc(&dev->_vblank_count[crtc]); /* Invalidate all timestamps while vblank irq's are off. */ @@ -1293,7 +1293,7 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc) * e.g., due to spurious vblank interrupts. We need to * ignore those for accounting. */ - if (abs(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { + if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { /* Store new timestamp in ringbuffer. */ vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; smp_wmb(); -- cgit v1.2.3 From bc21512835a72bc1eab7abd7d8a1bff0435591d7 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Mon, 21 Feb 2011 05:42:01 +0100 Subject: drm/vblank: Use memory barriers optimized for atomic_t instead of generics. Documentation/atomic_ops.txt tells us that there are memory barriers optimized for atomic_inc and other atomic_t ops. Use these instead of smp_wmb(), and also to make the required memory barriers around vblank counter increments more explicit. Signed-off-by: Mario Kleiner Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 6d2d4faf8678..22f3bf5ecbd2 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,8 +164,10 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc) * available. In that case we can't account for this and just * hope for the best. */ - if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) + if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { atomic_inc(&dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); + } /* Invalidate all timestamps while vblank irq's are off. */ clear_vblank_timestamps(dev, crtc); @@ -858,10 +860,11 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc) if (rc) { tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; vblanktimestamp(dev, crtc, tslot) = t_vblank; - smp_wmb(); } + smp_mb__before_atomic_inc(); atomic_add(diff, &dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); } /** @@ -1296,12 +1299,13 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc) if (abs64(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. */ + smp_mb__before_atomic_inc(); atomic_inc(&dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); } else { DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", crtc, (int) diff_ns); -- cgit v1.2.3 From 9be6f8a978bdcbab46474a125aa4212516b71fe7 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Mon, 21 Feb 2011 05:42:02 +0100 Subject: drm/vblank: Enable precise vblank timestamps for interlaced and doublescan modes. Testing showed the current code can already handle doublescan video modes just fine. A trivial tweak makes it work for interlaced scanout as well. Tested and shown to be precise on Radeon rv530, r600 and Intel 945-GME. Signed-off-by: Mario Kleiner Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 22f3bf5ecbd2..53120a72a48c 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -493,6 +493,12 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc) /* Dot clock in Hz: */ dotclock = (u64) crtc->hwmode.clock * 1000; + /* Fields of interlaced scanout modes are only halve a frame duration. + * Double the dotclock to get halve the frame-/line-/pixelduration. + */ + if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE) + dotclock *= 2; + /* Valid dotclock? */ if (dotclock > 0) { /* Convert scanline length in pixels and video dot clock to @@ -605,14 +611,6 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int 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. -- cgit v1.2.3 From 1922756124ddd53846877416d92ba4a802bc658f Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Thu, 24 Feb 2011 08:35:06 +1000 Subject: drm: fix unsigned vs signed comparison issue in modeset ctl ioctl. This fixes CVE-2011-1013. Reported-by: Matthiew Herrb (OpenBSD X.org team) Cc: stable@kernel.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 3 ++- include/drm/drmP.h | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 53120a72a48c..28d1d3c24d65 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1012,7 +1012,8 @@ int drm_modeset_ctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_modeset_ctl *modeset = data; - int crtc, ret = 0; + int ret = 0; + unsigned int crtc; /* If drm_vblank_init() hasn't been called yet, just no-op */ if (!dev->num_crtcs) diff --git a/include/drm/drmP.h b/include/drm/drmP.h index fe29aadb129d..348843b80150 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1101,7 +1101,7 @@ struct drm_device { struct platform_device *platformdev; /**< Platform device struture */ struct drm_sg_mem *sg; /**< Scatter gather memory */ - int num_crtcs; /**< Number of CRTCs on this device */ + unsigned int num_crtcs; /**< Number of CRTCs on this device */ void *dev_private; /**< device private data */ void *mm_private; struct address_space *dev_mapping; -- cgit v1.2.3