[PATCH 2/2] drm/msm/dpu: clean up some impossibilities

abhinavk at codeaurora.org abhinavk at codeaurora.org
Tue Sep 8 19:44:24 UTC 2020


On 2020-09-07 10:04, Rob Clark wrote:
> From: Rob Clark <robdclark at chromium.org>
> 
> Signed-off-by: Rob Clark <robdclark at chromium.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 81 ++++--------------------
>  1 file changed, 12 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 89c0245b5de5..ad49b0e17fcb 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -265,11 +265,6 @@ enum dpu_intf_mode dpu_crtc_get_intf_mode(struct
> drm_crtc *crtc)
>  {
>  	struct drm_encoder *encoder;
> 
> -	if (!crtc) {
> -		DPU_ERROR("invalid crtc\n");
> -		return INTF_MODE_NONE;
> -	}
> -
>  	/*
>  	 * TODO: This function is called from dpu debugfs and as part of 
> atomic
>  	 * check. When called from debugfs, the crtc->mutex must be held to
> @@ -500,12 +495,6 @@ static void dpu_crtc_atomic_begin(struct drm_crtc 
> *crtc,
>  	struct dpu_crtc_state *cstate;
>  	struct drm_encoder *encoder;
>  	struct drm_device *dev;
> -	unsigned long flags;
> -
> -	if (!crtc) {
> -		DPU_ERROR("invalid crtc\n");
> -		return;
> -	}
> 
>  	if (!crtc->state->enable) {
>  		DPU_DEBUG("crtc%d -> enable %d, skip atomic_begin\n",
> @@ -521,15 +510,6 @@ static void dpu_crtc_atomic_begin(struct drm_crtc 
> *crtc,
> 
>  	_dpu_crtc_setup_lm_bounds(crtc, crtc->state);
> 
> -	if (dpu_crtc->event) {
> -		WARN_ON(dpu_crtc->event);
> -	} else {
> -		spin_lock_irqsave(&dev->event_lock, flags);
> -		dpu_crtc->event = crtc->state->event;
> -		crtc->state->event = NULL;
> -		spin_unlock_irqrestore(&dev->event_lock, flags);
> -	}
> -
>  	/* encoder will trigger pending mask now */
>  	drm_for_each_encoder_mask(encoder, crtc->dev, 
> crtc->state->encoder_mask)
>  		dpu_encoder_trigger_kickoff_pending(encoder);
> @@ -583,14 +563,11 @@ static void dpu_crtc_atomic_flush(struct drm_crtc 
> *crtc,
>  		return;
>  	}
> 
> -	if (dpu_crtc->event) {
> -		DPU_DEBUG("already received dpu_crtc->event\n");
> -	} else {
> -		spin_lock_irqsave(&dev->event_lock, flags);
> -		dpu_crtc->event = crtc->state->event;
> -		crtc->state->event = NULL;
> -		spin_unlock_irqrestore(&dev->event_lock, flags);
> -	}
> +	WARN_ON(dpu_crtc->event);
before the patch "move vblank events to complete_commit()", the dpu_crtc 
events
were consumed in the _dpu_crtc_complete_flip(). So there was a chance 
that if the vblank event
did not come in time before the next commit, dpu_crtc->event will not be 
consumed.

But after the patch, _dpu_crtc_complete_flip() is being signaled in 
dpu_crtc_complete_commit()
which will always happen, so is there any case where we will hit this 
warning at all or will this
catch some other condition?

> +	spin_lock_irqsave(&dev->event_lock, flags);
> +	dpu_crtc->event = crtc->state->event;
> +	crtc->state->event = NULL;
> +	spin_unlock_irqrestore(&dev->event_lock, flags);
> 
>  	/*
>  	 * If no mixers has been allocated in dpu_crtc_atomic_check(),
> @@ -635,14 +612,7 @@ static void dpu_crtc_atomic_flush(struct drm_crtc 
> *crtc,
>  static void dpu_crtc_destroy_state(struct drm_crtc *crtc,
>  		struct drm_crtc_state *state)
>  {
> -	struct dpu_crtc_state *cstate;
> -
> -	if (!crtc || !state) {
> -		DPU_ERROR("invalid argument(s)\n");
> -		return;
> -	}
> -
> -	cstate = to_dpu_crtc_state(state);
> +	struct dpu_crtc_state *cstate = to_dpu_crtc_state(state);
> 
>  	DPU_DEBUG("crtc%d\n", crtc->base.id);
> 
> @@ -731,14 +701,8 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
>   */
>  static struct drm_crtc_state *dpu_crtc_duplicate_state(struct drm_crtc 
> *crtc)
>  {
> -	struct dpu_crtc_state *cstate, *old_cstate;
> -
> -	if (!crtc || !crtc->state) {
> -		DPU_ERROR("invalid argument(s)\n");
> -		return NULL;
> -	}
> +	struct dpu_crtc_state *cstate, *old_cstate = 
> to_dpu_crtc_state(crtc->state);
> 
> -	old_cstate = to_dpu_crtc_state(crtc->state);
>  	cstate = kmemdup(old_cstate, sizeof(*old_cstate), GFP_KERNEL);
>  	if (!cstate) {
>  		DPU_ERROR("failed to allocate state\n");
> @@ -754,19 +718,12 @@ static struct drm_crtc_state
> *dpu_crtc_duplicate_state(struct drm_crtc *crtc)
>  static void dpu_crtc_disable(struct drm_crtc *crtc,
>  			     struct drm_crtc_state *old_crtc_state)
>  {
> -	struct dpu_crtc *dpu_crtc;
> -	struct dpu_crtc_state *cstate;
> +	struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
> +	struct dpu_crtc_state *cstate = to_dpu_crtc_state(crtc->state);
>  	struct drm_encoder *encoder;
>  	unsigned long flags;
>  	bool release_bandwidth = false;
> 
> -	if (!crtc || !crtc->state) {
> -		DPU_ERROR("invalid crtc\n");
> -		return;
> -	}
> -	dpu_crtc = to_dpu_crtc(crtc);
> -	cstate = to_dpu_crtc_state(crtc->state);
> -
>  	DRM_DEBUG_KMS("crtc%d\n", crtc->base.id);
> 
>  	/* Disable/save vblank irq handling */
> @@ -825,19 +782,13 @@ static void dpu_crtc_disable(struct drm_crtc 
> *crtc,
>  static void dpu_crtc_enable(struct drm_crtc *crtc,
>  		struct drm_crtc_state *old_crtc_state)
>  {
> -	struct dpu_crtc *dpu_crtc;
> +	struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
>  	struct drm_encoder *encoder;
>  	bool request_bandwidth = false;
> 
> -	if (!crtc) {
> -		DPU_ERROR("invalid crtc\n");
> -		return;
> -	}
> -
>  	pm_runtime_get_sync(crtc->dev->dev);
> 
>  	DRM_DEBUG_KMS("crtc%d\n", crtc->base.id);
> -	dpu_crtc = to_dpu_crtc(crtc);
> 
>  	drm_for_each_encoder_mask(encoder, crtc->dev, 
> crtc->state->encoder_mask) {
>  		/* in video mode, we hold an extra bandwidth reference
> @@ -873,9 +824,9 @@ struct plane_state {
>  static int dpu_crtc_atomic_check(struct drm_crtc *crtc,
>  		struct drm_crtc_state *state)
>  {
> -	struct dpu_crtc *dpu_crtc;
> +	struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
> +	struct dpu_crtc_state *cstate = to_dpu_crtc_state(state);
>  	struct plane_state *pstates;
> -	struct dpu_crtc_state *cstate;
> 
>  	const struct drm_plane_state *pstate;
>  	struct drm_plane *plane;
> @@ -889,16 +840,8 @@ static int dpu_crtc_atomic_check(struct drm_crtc 
> *crtc,
>  	int left_zpos_cnt = 0, right_zpos_cnt = 0;
>  	struct drm_rect crtc_rect = { 0 };
> 
> -	if (!crtc) {
> -		DPU_ERROR("invalid crtc\n");
> -		return -EINVAL;
> -	}
> -
>  	pstates = kzalloc(sizeof(*pstates) * DPU_STAGE_MAX * 4, GFP_KERNEL);
> 
> -	dpu_crtc = to_dpu_crtc(crtc);
> -	cstate = to_dpu_crtc_state(state);
> -
>  	if (!state->enable || !state->active) {
>  		DPU_DEBUG("crtc%d -> enable %d, active %d, skip atomic_check\n",
>  				crtc->base.id, state->enable, state->active);


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