From 4706ca779a723913469a47bbdd63ede01681f0c4 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 19 Jul 2017 14:54:55 +0200 Subject: [PATCH] drm/i915: Unbreak gpu reset vs. modeset locking MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Taking the modeset locks unconditionally isn't the greatest idea, because atm that part is still broken and times out (and then atomic keels over). And there's really no reason to do so, the old code didn't do that either. To make the patch a bit simpler let's also nuke 2 cases that are only around for the old mmioflip paths. Atomic nonblocking workers will not die (minus bugs) when a gpu reset happens. And of course this doesn't fix any of the gpu reset vs. modeset deadlock fun, but it at least stop modern CI machines from keeling over all over the place for no reason at all. And we still have the explicit testcases to run the fake gpu reset, so coverage isn't that much worse. v2: Split out additional changes on top, restrict this to purely reducing the critical section of modeset locks. v2: Review from Maarten - update comments - don't oops when state is NULL in intel_finish_reset, but try to at least still drop locks properly. The hw is going to be toast anyway. Fixes: 739748939974 ("drm/i915: Fix modeset handling during gpu reset, v5.") Cc: Maarten Lankhorst Reviewed-by: Maarten Lankhorst Cc: Ville Syrjälä Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20170719125502.25696-3-daniel.vetter@ffwll.ch (cherry picked from commit ce87ea15ebc60a9f8f156b2549f7b2cf7fe48d04) Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_display.c | 60 +++++++++------------------- 1 file changed, 18 insertions(+), 42 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index ae4fb72a3394..e35daae00137 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3427,26 +3427,6 @@ static void intel_complete_page_flips(struct drm_i915_private *dev_priv) intel_finish_page_flip_cs(dev_priv, crtc->pipe); } -static void intel_update_primary_planes(struct drm_device *dev) -{ - struct drm_crtc *crtc; - - for_each_crtc(dev, crtc) { - struct intel_plane *plane = to_intel_plane(crtc->primary); - struct intel_plane_state *plane_state = - to_intel_plane_state(plane->base.state); - - if (plane_state->base.visible) { - trace_intel_update_plane(&plane->base, - to_intel_crtc(crtc)); - - plane->update_plane(plane, - to_intel_crtc_state(crtc->state), - plane_state); - } - } -} - static int __intel_display_resume(struct drm_device *dev, struct drm_atomic_state *state, @@ -3499,6 +3479,12 @@ void intel_prepare_reset(struct drm_i915_private *dev_priv) struct drm_atomic_state *state; int ret; + + /* reset doesn't touch the display */ + if (!i915.force_reset_modeset_test && + !gpu_reset_clobbers_display(dev_priv)) + return; + /* * Need mode_config.mutex so that we don't * trample ongoing ->detect() and whatnot. @@ -3512,12 +3498,6 @@ void intel_prepare_reset(struct drm_i915_private *dev_priv) drm_modeset_backoff(ctx); } - - /* reset doesn't touch the display, but flips might get nuked anyway, */ - if (!i915.force_reset_modeset_test && - !gpu_reset_clobbers_display(dev_priv)) - return; - /* * Disabling the crtcs gracefully seems nicer. Also the * g33 docs say we should at least disable all the planes. @@ -3547,6 +3527,14 @@ void intel_finish_reset(struct drm_i915_private *dev_priv) struct drm_atomic_state *state = dev_priv->modeset_restore_state; int ret; + /* reset doesn't touch the display */ + if (!i915.force_reset_modeset_test && + !gpu_reset_clobbers_display(dev_priv)) + return; + + if (!state) + goto unlock; + /* * Flips in the rings will be nuked by the reset, * so complete all pending flips so that user space @@ -3558,22 +3546,10 @@ void intel_finish_reset(struct drm_i915_private *dev_priv) /* reset doesn't touch the display */ if (!gpu_reset_clobbers_display(dev_priv)) { - if (!state) { - /* - * Flips in the rings have been nuked by the reset, - * so update the base address of all primary - * planes to the the last fb to make sure we're - * showing the correct fb after a reset. - * - * FIXME: Atomic will make this obsolete since we won't schedule - * CS-based flips (which might get lost in gpu resets) any more. - */ - intel_update_primary_planes(dev); - } else { - ret = __intel_display_resume(dev, state, ctx); + /* for testing only restore the display */ + ret = __intel_display_resume(dev, state, ctx); if (ret) DRM_ERROR("Restoring old state failed with %i\n", ret); - } } else { /* * The display has been reset as well, @@ -3597,8 +3573,8 @@ void intel_finish_reset(struct drm_i915_private *dev_priv) intel_hpd_init(dev_priv); } - if (state) - drm_atomic_state_put(state); + drm_atomic_state_put(state); +unlock: drm_modeset_drop_locks(ctx); drm_modeset_acquire_fini(ctx); mutex_unlock(&dev->mode_config.mutex); -- 2.20.1