Op 10-05-16 om 09:48 schreef Daniel Vetter:
> On Mon, May 09, 2016 at 03:54:15PM +0300, Ville Syrjälä wrote:
>> On Mon, May 09, 2016 at 01:04:21PM +0200, Maarten Lankhorst wrote:
>>> This function would call drm_modeset_lock_all, while the suspend/resume
>>> functions already have their own locking. Fix this by factoring out
>>> __intel_display_resume, and calling the atomic helpers for duplicating
>>> atomic state and disabling all crtc's during suspend.
>>>
>>> Changes since v1:
>>> - Deal with -EDEADLK right after lock_all and clean up calls
>>>   to hw readout.
>>> - Always take all modeset locks so updates during gpu reset are blocked.
>>> Changes since v2:
>>> - Fix deadlock in intel_update_primary_planes.
>>> - Move WARN_ON(EDEADLK) to __intel_display_resume.
>>> - pctx -> ctx
>>> - only call __intel_display_resume on success in intel_display_resume.
>>>
>>> Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
>>> Fixes: e2c8b8701e2d ("drm/i915: Use atomic helpers for suspend, v2.")
>>> Cc: drm-intel-fi...@lists.freedesktop.org
>>> ---
>>>  drivers/gpu/drm/i915/intel_display.c | 150 
>>> ++++++++++++++++++++++-------------
>>>  1 file changed, 93 insertions(+), 57 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_display.c 
>>> b/drivers/gpu/drm/i915/intel_display.c
>>> index 14e05091c397..6faa529f35df 100644
>>> --- a/drivers/gpu/drm/i915/intel_display.c
>>> +++ b/drivers/gpu/drm/i915/intel_display.c
>>> @@ -3130,41 +3130,96 @@ static void intel_update_primary_planes(struct 
>>> drm_device *dev)
>>>  
>>>     for_each_crtc(dev, crtc) {
>>>             struct intel_plane *plane = to_intel_plane(crtc->primary);
>>> -           struct intel_plane_state *plane_state;
>>> -
>>> -           drm_modeset_lock_crtc(crtc, &plane->base);
>>> -           plane_state = to_intel_plane_state(plane->base.state);
>>> +           struct intel_plane_state *plane_state =
>>> +                   to_intel_plane_state(plane->base.state);
>>>  
>>>             if (plane_state->visible)
>>>                     plane->update_plane(&plane->base,
>>>                                         to_intel_crtc_state(crtc->state),
>>>                                         plane_state);
>>> +   }
>>> +}
>>> +
>>> +static int
>>> +__intel_display_resume(struct drm_device *dev,
>>> +                  struct drm_atomic_state *state)
>>> +{
>>> +   struct drm_crtc_state *crtc_state;
>>> +   struct drm_crtc *crtc;
>>> +   int i, ret;
>>> +
>>> +   intel_modeset_setup_hw_state(dev);
>>> +   i915_redisable_vga(dev);
>>>  
>>> -           drm_modeset_unlock_crtc(crtc);
>>> +   if (!state)
>>> +           return 0;
>> Thank you diff for making things illegible.
>>
>> I'm still not convinced we should be changing the locking scheme
>> here, especially in what's supposed to be just a fix.
>>
>> In general, I'm not sure we want ->detect() and other irrelevant
>> stuff to block the GPU reset. The nice thing about g4x+ reset so
>> far has been that it's almost unnoticeable. Of course if it's a
>> genuine GPU hang the screen will probably have been frozen for
>> quite a while when we initiate the reset, so perhaps that's not
>> a huge real world issue.
> We don't really need dev->mode_config.mutex for atomic commits, so taking
> that out and use drm_modeset_lock_all_ctx would give you that.
> -Daniel

---->8----

This function would call drm_modeset_lock_all, while the suspend/resume
functions already have their own locking. Fix this by factoring out
__intel_display_resume, and calling the atomic helpers for duplicating
atomic state and disabling all crtc's during suspend.

Changes since v1:
- Deal with -EDEADLK right after lock_all and clean up calls
  to hw readout.
- Always take all modeset locks so updates during gpu reset are blocked.
Changes since v2:
- Fix deadlock in intel_update_primary_planes.
- Move WARN_ON(EDEADLK) to __intel_display_resume.
- pctx -> ctx
- only call __intel_display_resume on success in intel_display_resume.
Changes since v3:
- Rebase on top of dev_priv -> dev change.
- Use drm_modeset_lock_all_ctx instead of drm_modeset_lock_all.

Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Fixes: e2c8b8701e2d ("drm/i915: Use atomic helpers for suspend, v2.")
Cc: drm-intel-fi...@lists.freedesktop.org
---
 drivers/gpu/drm/i915/i915_drv.h      |   1 +
 drivers/gpu/drm/i915/intel_display.c | 164 +++++++++++++++++++++++------------
 2 files changed, 109 insertions(+), 56 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4abd39f32c0f..422e551937f7 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1835,6 +1835,7 @@ struct drm_i915_private {
        enum modeset_restore modeset_restore;
        struct mutex modeset_restore_lock;
        struct drm_atomic_state *modeset_restore_state;
+       struct drm_modeset_acquire_ctx reset_ctx;
 
        struct list_head vm_list; /* Global list of all address spaces */
        struct i915_ggtt ggtt; /* VM representing the global address space */
diff --git a/drivers/gpu/drm/i915/intel_display.c 
b/drivers/gpu/drm/i915/intel_display.c
index 138ed1aa3938..e88a942787c5 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3130,40 +3130,109 @@ static void intel_update_primary_planes(struct 
drm_device *dev)
 
        for_each_crtc(dev, crtc) {
                struct intel_plane *plane = to_intel_plane(crtc->primary);
-               struct intel_plane_state *plane_state;
-
-               drm_modeset_lock_crtc(crtc, &plane->base);
-               plane_state = to_intel_plane_state(plane->base.state);
+               struct intel_plane_state *plane_state =
+                       to_intel_plane_state(plane->base.state);
 
                if (plane_state->visible)
                        plane->update_plane(&plane->base,
                                            to_intel_crtc_state(crtc->state),
                                            plane_state);
+       }
+}
+
+static int
+__intel_display_resume(struct drm_device *dev,
+                      struct drm_atomic_state *state)
+{
+       struct drm_crtc_state *crtc_state;
+       struct drm_crtc *crtc;
+       int i, ret;
+
+       intel_modeset_setup_hw_state(dev);
+       i915_redisable_vga(dev);
 
-               drm_modeset_unlock_crtc(crtc);
+       if (!state)
+               return 0;
+
+       for_each_crtc_in_state(state, crtc, crtc_state, i) {
+               /*
+                * Force recalculation even if we restore
+                * current state. With fast modeset this may not result
+                * in a modeset when the state is compatible.
+                */
+               crtc_state->mode_changed = true;
        }
+
+       ret = drm_atomic_commit(state);
+
+       WARN_ON(ret == -EDEADLK);
+       return ret;
 }
 
 void intel_prepare_reset(struct drm_i915_private *dev_priv)
 {
+       struct drm_atomic_state *state;
+       struct drm_modeset_acquire_ctx *ctx;
+       int ret;
+
        /* no reset support for gen2 */
        if (IS_GEN2(dev_priv))
                return;
 
-       /* reset doesn't touch the display */
+       ctx = &dev_priv->reset_ctx;
+
+       /*
+        * This is a cludge because with real atomic modeset mode_config.mutex
+        * won't be taken. Unfortunately some probed state like
+        * audio_codec_enable is still protected by mode_config.mutex, so lock
+        * it here for now.
+        */
+       mutex_lock(&dev_priv->dev->mode_config.mutex);
+       drm_modeset_acquire_init(ctx, 0);
+       while (1) {
+               ret = drm_modeset_lock_all_ctx(dev_priv->dev, ctx);
+               if (ret != -EDEADLK)
+                       break;
+
+               drm_modeset_backoff(ctx);
+       }
+
+       /* reset doesn't touch the display, but flips might get nuked anyway, */
        if (INTEL_GEN(dev_priv) >= 5 || IS_G4X(dev_priv))
                return;
 
-       drm_modeset_lock_all(dev_priv->dev);
        /*
         * Disabling the crtcs gracefully seems nicer. Also the
         * g33 docs say we should at least disable all the planes.
         */
-       intel_display_suspend(dev_priv->dev);
+       state = drm_atomic_helper_duplicate_state(dev_priv->dev, ctx);
+       if (IS_ERR(state)) {
+               ret = PTR_ERR(state);
+               state = NULL;
+               DRM_ERROR("Duplicating state failed with %i\n", ret);
+               goto err;
+       }
+
+       ret = drm_atomic_helper_disable_all(dev_priv->dev, ctx);
+       if (ret) {
+               DRM_ERROR("Suspending crtc's failed with %i\n", ret);
+               goto err;
+       }
+
+       dev_priv->modeset_restore_state = state;
+       state->acquire_ctx = ctx;
+       return;
+
+err:
+       drm_atomic_state_free(state);
 }
 
 void intel_finish_reset(struct drm_i915_private *dev_priv)
 {
+       struct drm_atomic_state *state = dev_priv->modeset_restore_state;
+       struct drm_modeset_acquire_ctx *ctx = &dev_priv->reset_ctx;
+       int ret;
+
        /*
         * Flips in the rings will be nuked by the reset,
         * so complete all pending flips so that user space
@@ -3175,6 +3244,8 @@ void intel_finish_reset(struct drm_i915_private *dev_priv)
        if (IS_GEN2(dev_priv))
                return;
 
+       dev_priv->modeset_restore_state = NULL;
+
        /* reset doesn't touch the display */
        if (INTEL_GEN(dev_priv) >= 5 || IS_G4X(dev_priv)) {
                /*
@@ -3187,28 +3258,31 @@ void intel_finish_reset(struct drm_i915_private 
*dev_priv)
                 * CS-based flips (which might get lost in gpu resets) any more.
                 */
                intel_update_primary_planes(dev_priv->dev);
-               return;
-       }
-
-       /*
-        * The display has been reset as well,
-        * so need a full re-initialization.
-        */
-       intel_runtime_pm_disable_interrupts(dev_priv);
-       intel_runtime_pm_enable_interrupts(dev_priv);
+       } else {
+               /*
+               * The display has been reset as well,
+               * so need a full re-initialization.
+               */
+               intel_runtime_pm_disable_interrupts(dev_priv);
+               intel_runtime_pm_enable_interrupts(dev_priv);
 
-       intel_modeset_init_hw(dev_priv->dev);
+               intel_modeset_init_hw(dev_priv->dev);
 
-       spin_lock_irq(&dev_priv->irq_lock);
-       if (dev_priv->display.hpd_irq_setup)
-               dev_priv->display.hpd_irq_setup(dev_priv);
-       spin_unlock_irq(&dev_priv->irq_lock);
+               spin_lock_irq(&dev_priv->irq_lock);
+               if (dev_priv->display.hpd_irq_setup)
+                       dev_priv->display.hpd_irq_setup(dev_priv);
+               spin_unlock_irq(&dev_priv->irq_lock);
 
-       intel_display_resume(dev_priv->dev);
+               ret = __intel_display_resume(dev_priv->dev, state);
+               if (ret)
+                       DRM_ERROR("Restoring old state failed with %i\n", ret);
 
-       intel_hpd_init(dev_priv);
+               intel_hpd_init(dev_priv);
+       }
 
-       drm_modeset_unlock_all(dev_priv->dev);
+       drm_modeset_drop_locks(ctx);
+       drm_modeset_acquire_fini(ctx);
+       mutex_unlock(&dev_priv->dev->mode_config.mutex);
 }
 
 static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc)
@@ -15957,9 +16031,10 @@ void intel_display_resume(struct drm_device *dev)
        struct drm_atomic_state *state = dev_priv->modeset_restore_state;
        struct drm_modeset_acquire_ctx ctx;
        int ret;
-       bool setup = false;
 
        dev_priv->modeset_restore_state = NULL;
+       if (state)
+               state->acquire_ctx = &ctx;
 
        /*
         * This is a cludge because with real atomic modeset mode_config.mutex
@@ -15970,40 +16045,17 @@ void intel_display_resume(struct drm_device *dev)
        mutex_lock(&dev->mode_config.mutex);
        drm_modeset_acquire_init(&ctx, 0);
 
-retry:
-       ret = drm_modeset_lock_all_ctx(dev, &ctx);
-
-       if (ret == 0 && !setup) {
-               setup = true;
-
-               intel_modeset_setup_hw_state(dev);
-               i915_redisable_vga(dev);
-       }
-
-       if (ret == 0 && state) {
-               struct drm_crtc_state *crtc_state;
-               struct drm_crtc *crtc;
-               int i;
-
-               state->acquire_ctx = &ctx;
-
-               for_each_crtc_in_state(state, crtc, crtc_state, i) {
-                       /*
-                        * Force recalculation even if we restore
-                        * current state. With fast modeset this may not result
-                        * in a modeset when the state is compatible.
-                        */
-                       crtc_state->mode_changed = true;
-               }
-
-               ret = drm_atomic_commit(state);
-       }
+       while (1) {
+               ret = drm_modeset_lock_all_ctx(dev, &ctx);
+               if (ret != -EDEADLK)
+                       break;
 
-       if (ret == -EDEADLK) {
                drm_modeset_backoff(&ctx);
-               goto retry;
        }
 
+       if (!ret)
+               ret = __intel_display_resume(dev, state);
+
        drm_modeset_drop_locks(&ctx);
        drm_modeset_acquire_fini(&ctx);
        mutex_unlock(&dev->mode_config.mutex);
-- 
2.5.5


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