Re: [PATCH 1/5] drm/i915: Make plane fb tracking work correctly, v2.

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Op 14-10-15 om 14:59 schreef Ander Conselvan De Oliveira:
> On Wed, 2015-09-23 at 13:27 +0200, Maarten Lankhorst wrote:
>> atomic->disabled_planes is a hack that had to exist because
>> prepare_fb was only called when a new fb was set. This messed
>> up fb tracking in some circumstances like aborts from
>> interruptible waits. As a result interruptible waiting in
>> prepare_plane_fb was forbidden, but other errors could still
>> cause frontbuffer tracking to be messed up.
>>
>> Now that prepare_fb is always called, this hack is no longer
>> required and prepare_fb may fail without consequences.
>>
>> Changes since v1:
>> - Clean up a few fb tracking warnings by changing plane->fb to
>>   plane->state->fb.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_display.c | 47 ++++++++++++++----------------------
>>  drivers/gpu/drm/i915/intel_drv.h     |  1 -
>>  2 files changed, 18 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index fc0086748b71..ac97af69be62 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -4752,17 +4752,6 @@ static void intel_pre_plane_update(struct intel_crtc *crtc)
>>  	struct drm_device *dev = crtc->base.dev;
>>  	struct drm_i915_private *dev_priv = dev->dev_private;
>>  	struct intel_crtc_atomic_commit *atomic = &crtc->atomic;
>> -	struct drm_plane *p;
>> -
>> -	/* Track fb's for any planes being disabled */
>> -	drm_for_each_plane_mask(p, dev, atomic->disabled_planes) {
>> -		struct intel_plane *plane = to_intel_plane(p);
>> -
>> -		mutex_lock(&dev->struct_mutex);
>> -		i915_gem_track_fb(intel_fb_obj(plane->base.fb), NULL,
>> -				  plane->frontbuffer_bit);
>> -		mutex_unlock(&dev->struct_mutex);
>> -	}
>>  
>>  	if (atomic->wait_for_flips)
>>  		intel_crtc_wait_for_pending_flips(&crtc->base);
>> @@ -11561,14 +11550,6 @@ int intel_plane_atomic_calc_changes(struct drm_crtc_state *crtc_state,
>>  			return ret;
>>  	}
>>  
>> -	/*
>> -	 * Disabling a plane is always okay; we just need to update
>> -	 * fb tracking in a special way since cleanup_fb() won't
>> -	 * get called by the plane helpers.
>> -	 */
>> -	if (old_plane_state->base.fb && !fb)
>> -		intel_crtc->atomic.disabled_planes |= 1 << i;
>> -
>>  	was_visible = old_plane_state->visible;
>>  	visible = to_intel_plane_state(plane_state)->visible;
>>  
>> @@ -13318,15 +13299,17 @@ intel_prepare_plane_fb(struct drm_plane *plane,
>>  	struct drm_framebuffer *fb = new_state->fb;
>>  	struct intel_plane *intel_plane = to_intel_plane(plane);
>>  	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
>> -	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->fb);
>> +	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);
>>  	int ret = 0;
>>  
>> -	if (!obj)
>> +	if (!obj && !old_obj)
>>  		return 0;
>>  
>>  	mutex_lock(&dev->struct_mutex);
>>  
>> -	if (plane->type == DRM_PLANE_TYPE_CURSOR &&
>> +	if (!obj) {
>> +		ret = 0;
>> +	} else if (plane->type == DRM_PLANE_TYPE_CURSOR &&
>>  	    INTEL_INFO(dev)->cursor_needs_physical) {
>>  		int align = IS_I830(dev) ? 16 * 1024 : 256;
>>  		ret = i915_gem_object_attach_phys(obj, align);
>> @@ -13356,17 +13339,23 @@ intel_cleanup_plane_fb(struct drm_plane *plane,
>>  		       const struct drm_plane_state *old_state)
>>  {
>>  	struct drm_device *dev = plane->dev;
>> -	struct drm_i915_gem_object *obj = intel_fb_obj(old_state->fb);
>> +	struct intel_plane *intel_plane = to_intel_plane(plane);
>> +	struct drm_i915_gem_object *old_obj = intel_fb_obj(old_state->fb);
>> +	struct drm_i915_gem_object *obj = intel_fb_obj(plane->state->fb);
>>  
>> -	if (!obj)
>> +	if (!obj && !old_obj)
>>  		return;
>>  
>> -	if (plane->type != DRM_PLANE_TYPE_CURSOR ||
>> -	    !INTEL_INFO(dev)->cursor_needs_physical) {
>> -		mutex_lock(&dev->struct_mutex);
>> +	mutex_lock(&dev->struct_mutex);
>> +	if (old_obj && (plane->type != DRM_PLANE_TYPE_CURSOR ||
>> +	    !INTEL_INFO(dev)->cursor_needs_physical))
>>  		intel_unpin_fb_obj(old_state->fb, old_state);
>> -		mutex_unlock(&dev->struct_mutex);
>> -	}
>> +
>> +	/* prepare_fb aborted? */
>> +	if ((old_obj && (old_obj->frontbuffer_bits & intel_plane->frontbuffer_bit)) ||
>> +	    (obj && !(obj->frontbuffer_bits & intel_plane->frontbuffer_bit)))
>> +		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);
> I'm not a fan of this big condition. Would it make sense to add a new parameter to cleanup_fb() that
> tells us if this is an abort clean up?
>
> But in any case, that can be done later.
>
> Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
>
This is only temporarily though. I plan to make unpin async in the future. When that happens cleanup_fb will only be called when aborting so it will become a moot point. :)
We could also add a force flag to i915_gem_track_fb to ignore warnings in cleanup_plane_fb later on.

~Maarten
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