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Message-ID: <010101746f3f7b59-bd6c1de2-1fae-4733-ba95-a4802b81b892-000000@us-west-2.amazonses.com>
Date: Tue, 8 Sep 2020 19:44:25 +0000
From: abhinavk@...eaurora.org
To: Rob Clark <robdclark@...il.com>
Cc: dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
freedreno@...ts.freedesktop.org,
Rob Clark <robdclark@...omium.org>,
Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Drew Davenport <ddavenport@...omium.org>,
Kalyan Thota <kalyan_t@...eaurora.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
Hongbo Yao <yaohongbo@...wei.com>,
linux-kernel@...r.kernel.org, linux-arm-msm-owner@...r.kernel.org
Subject: Re: [PATCH 2/2] drm/msm/dpu: clean up some impossibilities
On 2020-09-07 10:04, Rob Clark wrote:
> From: Rob Clark <robdclark@...omium.org>
>
> Signed-off-by: Rob Clark <robdclark@...omium.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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