In an attempt to get to the bottom of bug #29798, Chris Wilson gave me a patch that put some details in debugfs. With the clues gathered from that patch, I was able to determine that the page flip is happening, but that we're not seeing the IRQs we'd expect.
Work around this by only permitting a pageflip to be outstanding for 3 VBlank periods before we start examining the display registers to see if the pageflip happened, but we weren't told about it. This converts an apparent hang into a visual glitch. Signed-off-by: Simon Farnsworth <[email protected]> --- drivers/gpu/drm/i915/i915_debugfs.c | 45 +++++++++++++++++++++++++++ drivers/gpu/drm/i915/i915_irq.c | 56 ++++++++++++++++++++++++++++++++- drivers/gpu/drm/i915/intel_display.c | 15 +++------ drivers/gpu/drm/i915/intel_drv.h | 10 ++++++ 4 files changed, 114 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 92d5605..2879ab1 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -33,6 +33,7 @@ #include "drm.h" #include "i915_drm.h" #include "i915_drv.h" +#include "intel_drv.h" #define DRM_I915_RING_DEBUG 1 @@ -121,6 +122,49 @@ static int i915_gem_object_list_info(struct seq_file *m, void *data) return 0; } +static int i915_gem_pageflip_info(struct seq_file *m, void *data) +{ + struct drm_info_node *node = (struct drm_info_node *) m->private; + struct drm_device *dev = node->minor->dev; + unsigned long flags; + struct intel_crtc *crtc; + + list_for_each_entry(crtc, &dev->mode_config.crtc_list, base.head) { + const char *pipe = crtc->pipe ? "B" : "A"; + const char *plane = crtc->plane ? "B" : "A"; + struct intel_unpin_work *work; + + spin_lock_irqsave(&dev->event_lock, flags); + work = crtc->unpin_work; + if (work == NULL) { + seq_printf(m, "No flip due on pipe %s (plane %s)\n", + pipe, plane); + } else { + if (!work->pending) { + seq_printf(m, "Flip queued on pipe %s (plane %s)\n", + pipe, plane); + } else { + seq_printf(m, "Flip pending (waiting for vsync) on pipe %s (plane %s)\n", + pipe, plane); + } + seq_printf(m, "%d vblanks before missed interrupt check, %d prepares\n", work->stall_check_vblanks, work->pending); + if (work->old_fb_obj) { + struct drm_i915_gem_object *obj_priv = to_intel_bo(work->old_fb_obj); + if(obj_priv) + seq_printf(m, "Old framebuffer gtt_offset 0x%08x\n", obj_priv->gtt_offset ); + } + if (work->pending_flip_obj) { + struct drm_i915_gem_object *obj_priv = to_intel_bo(work->pending_flip_obj); + if(obj_priv) + seq_printf(m, "New framebuffer gtt_offset 0x%08x\n", obj_priv->gtt_offset ); + } + } + spin_unlock_irqrestore(&dev->event_lock, flags); + } + + return 0; +} + static int i915_gem_request_info(struct seq_file *m, void *data) { struct drm_info_node *node = (struct drm_info_node *) m->private; @@ -777,6 +821,7 @@ static struct drm_info_list i915_debugfs_list[] = { {"i915_gem_active", i915_gem_object_list_info, 0, (void *) ACTIVE_LIST}, {"i915_gem_flushing", i915_gem_object_list_info, 0, (void *) FLUSHING_LIST}, {"i915_gem_inactive", i915_gem_object_list_info, 0, (void *) INACTIVE_LIST}, + {"i915_gem_pageflip", i915_gem_pageflip_info, 0}, {"i915_gem_request", i915_gem_request_info, 0}, {"i915_gem_seqno", i915_gem_seqno_info, 0}, {"i915_gem_fence_regs", i915_gem_fence_regs_info, 0}, diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 16861b8..893cd77 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -887,6 +887,54 @@ static void i915_handle_error(struct drm_device *dev, bool wedged) queue_work(dev_priv->wq, &dev_priv->error_work); } +static void i915_pageflip_stall_check(struct drm_device *dev, int pipe) +{ + drm_i915_private_t *dev_priv = dev->dev_private; + struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe]; + int plane = intel_crtc->plane; + struct intel_crtc *intel_crtc = to_intel_crtc(crtc); + unsigned long flags; + bool stall_detected = false; + struct drm_i915_gem_object *obj_priv; + + /* Ignore early vblank irqs */ + if (intel_crtc == NULL) + return; + + spin_lock_irqsave(&dev->event_lock, flags); + work = intel_crtc->unpin_work; + + if (work == NULL || work->pending || !work->pending_flip_obj) { + /* Not started - can't have stalled */ + spin_unlock_irqrestore(&dev->event_lock, flags); + return; + } + if (work->stall_check_vblanks > 0) { + --work->stall_check_vblanks; + spin_unlock_irqrestore(&dev->event_lock, flags); + return; + } + + /* Potential stall */ + obj_priv = to_intel_bo(work->pending_flip_obj); + if(IS_I965G(dev)) { + int dspsurf = (plane == 0 ? DSPASURF : DSPBSURF); + stall_detected = I915_READ(dspsurf) == obj_priv->gtt_offset; + } + else { + int dspaddr = (plane == 0 ? DSPAADDR : DSPBADDR); + stall_detected = I915_READ(dspaddr) == (obj_priv->gtt_offset + + crtc->y * crtc->fb->pitch + + crtc->x * crtc->fb->bits_per_pixel/8); + } + + spin_unlock_irqrestore(&dev->event_lock, flags); + + if (stall_detected) + intel_prepare_page_flip(dev, plane); + return; +} + irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS) { struct drm_device *dev = (struct drm_device *) arg; @@ -1004,15 +1052,19 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS) if (pipea_stats & vblank_status) { vblank++; drm_handle_vblank(dev, 0); - if (!dev_priv->flip_pending_is_done) + if (!dev_priv->flip_pending_is_done) { + i915_pageflip_stall_check(dev, 0); intel_finish_page_flip(dev, 0); + } } if (pipeb_stats & vblank_status) { vblank++; drm_handle_vblank(dev, 1); - if (!dev_priv->flip_pending_is_done) + if (!dev_priv->flip_pending_is_done) { + i915_pageflip_stall_check(dev, 1); intel_finish_page_flip(dev, 1); + } } if ((pipea_stats & PIPE_LEGACY_BLC_EVENT_STATUS) || diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 23157e1..c8f2624 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4911,15 +4911,6 @@ static void intel_crtc_destroy(struct drm_crtc *crtc) kfree(intel_crtc); } -struct intel_unpin_work { - struct work_struct work; - struct drm_device *dev; - struct drm_gem_object *old_fb_obj; - struct drm_gem_object *pending_flip_obj; - struct drm_pending_vblank_event *event; - int pending; -}; - static void intel_unpin_work_fn(struct work_struct *__work) { struct intel_unpin_work *work = @@ -5007,7 +4998,7 @@ void intel_prepare_page_flip(struct drm_device *dev, int plane) spin_lock_irqsave(&dev->event_lock, flags); if (intel_crtc->unpin_work) { - intel_crtc->unpin_work->pending = 1; + ++intel_crtc->unpin_work->pending; } else { DRM_DEBUG_DRIVER("preparing flip with no unpin work?\n"); } @@ -5049,6 +5040,10 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, DRM_DEBUG_DRIVER("flip queue: crtc already busy\n"); return -EBUSY; } + /* Long enough to allow for one coming in while we were setting this up, + one while we fill in the ring, and finally the one that should have + resulted in the flip happening */ + work->stall_check_vblanks = 3; intel_crtc->unpin_work = work; spin_unlock_irqrestore(&dev->event_lock, flags); diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 0e92aa0..db8725b 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -176,6 +176,16 @@ struct intel_crtc { #define enc_to_intel_encoder(x) container_of(x, struct intel_encoder, enc) #define to_intel_framebuffer(x) container_of(x, struct intel_framebuffer, base) +struct intel_unpin_work { + struct work_struct work; + struct drm_device *dev; + struct drm_gem_object *old_fb_obj; + struct drm_gem_object *pending_flip_obj; + struct drm_pending_vblank_event *event; + int pending; + int stall_check_vblanks; +}; + struct i2c_adapter *intel_i2c_create(struct drm_device *dev, const u32 reg, const char *name); void intel_i2c_destroy(struct i2c_adapter *adapter); -- 1.7.0.1 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
