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Message-ID: <fc45b986-99ae-b63d-9ed4-0ca622b16a8f@linaro.org>
Date: Tue, 13 Sep 2022 20:04:49 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Vinod Polimera <quic_vpolimer@...cinc.com>,
dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, robdclark@...il.com,
dianders@...omium.org, swboyd@...omium.org,
quic_kalyant@...cinc.com, quic_khsieh@...cinc.com,
quic_vproddut@...cinc.com, quic_bjorande@...cinc.com,
quic_aravindh@...cinc.com, quic_abhinavk@...cinc.com,
quic_sbillaka@...cinc.com
Subject: Re: [PATCH v7 01/15] drm/msm/disp/dpu: clear dpu_assign_crtc and get
crtc from connector state instead of dpu_enc
On 13/09/2022 17:51, Vinod Polimera wrote:
> Update crtc retrieval from dpu_enc to dpu_enc connector state,
> since new links get set as part of the dpu enc virt mode set.
> The dpu_enc->crtc cache is no more needed, hence cleaning it as
> part of this change.
>
> Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 4 ----
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 35 ++++++++++++-----------------
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h | 8 -------
> 3 files changed, 14 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 13ce321..8ec9a13 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -1029,7 +1029,6 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
> */
> if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
> release_bandwidth = true;
> - dpu_encoder_assign_crtc(encoder, NULL);
> }
>
> /* wait for frame_event_done completion */
> @@ -1099,9 +1098,6 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
> trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
> dpu_crtc->enabled = true;
>
> - drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
> - dpu_encoder_assign_crtc(encoder, crtc);
> -
> /* Enable/restore vblank irq handling */
> drm_crtc_vblank_on(crtc);
> }
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 9c6817b..0c7d8b5 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -132,11 +132,6 @@ enum dpu_enc_rc_states {
> * @intfs_swapped: Whether or not the phys_enc interfaces have been swapped
> * for partial update right-only cases, such as pingpong
> * split where virtual pingpong does not generate IRQs
> - * @crtc: Pointer to the currently assigned crtc. Normally you
> - * would use crtc->state->encoder_mask to determine the
> - * link between encoder/crtc. However in this case we need
> - * to track crtc in the disable() hook which is called
> - * _after_ encoder_mask is cleared.
> * @connector: If a mode is set, cached pointer to the active connector
> * @crtc_kickoff_cb: Callback into CRTC that will flush & start
> * all CTL paths
> @@ -181,7 +176,6 @@ struct dpu_encoder_virt {
>
> bool intfs_swapped;
>
> - struct drm_crtc *crtc;
> struct drm_connector *connector;
>
> struct dentry *debugfs_root;
> @@ -1288,6 +1282,7 @@ static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
> struct dpu_encoder_phys *phy_enc)
> {
> struct dpu_encoder_virt *dpu_enc = NULL;
> + struct drm_crtc *crtc;
> unsigned long lock_flags;
>
> if (!drm_enc || !phy_enc)
> @@ -1298,9 +1293,14 @@ static void dpu_encoder_vblank_callback(struct drm_encoder *drm_enc,
>
> atomic_inc(&phy_enc->vsync_cnt);
>
> + if (!dpu_enc->connector || !dpu_enc->connector->state)
> + return;
> +
> + crtc = dpu_enc->connector->state->crtc;
> +
> spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> - if (dpu_enc->crtc)
> - dpu_crtc_vblank_callback(dpu_enc->crtc);
> + if (crtc)
> + dpu_crtc_vblank_callback(crtc);
> spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
Stephen's comment about reading the state from outside of the lock and
then using local variable under spinlock is still valid. Moreover I'm
not sure that enc_spinlock protects connector's state. I'd say one has
to take the modesetting lock here.
>
> DPU_ATRACE_END("encoder_vblank_callback");
> @@ -1324,29 +1324,22 @@ static void dpu_encoder_underrun_callback(struct drm_encoder *drm_enc,
> DPU_ATRACE_END("encoder_underrun_callback");
> }
>
> -void dpu_encoder_assign_crtc(struct drm_encoder *drm_enc, struct drm_crtc *crtc)
> -{
> - struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
> - unsigned long lock_flags;
> -
> - spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> - /* crtc should always be cleared before re-assigning */
> - WARN_ON(crtc && dpu_enc->crtc);
> - dpu_enc->crtc = crtc;
> - spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
> -}
> -
> void dpu_encoder_toggle_vblank_for_crtc(struct drm_encoder *drm_enc,
> struct drm_crtc *crtc, bool enable)
> {
> struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
> + struct drm_crtc *new_crtc;
> unsigned long lock_flags;
> int i;
>
> trace_dpu_enc_vblank_cb(DRMID(drm_enc), enable);
>
> + if (!dpu_enc->connector || !dpu_enc->connector->state)
> + return;
> +
> + new_crtc = dpu_enc->connector->state->crtc;
> spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
> - if (dpu_enc->crtc != crtc) {
> + if (!new_crtc || new_crtc != crtc) {
> spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
> return;
> }
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> index 9e7236e..eda5cd8 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> @@ -40,14 +40,6 @@ struct msm_display_info {
> };
>
> /**
> - * dpu_encoder_assign_crtc - Link the encoder to the crtc it's assigned to
> - * @encoder: encoder pointer
> - * @crtc: crtc pointer
> - */
> -void dpu_encoder_assign_crtc(struct drm_encoder *encoder,
> - struct drm_crtc *crtc);
> -
> -/**
> * dpu_encoder_toggle_vblank_for_crtc - Toggles vblank interrupts on or off if
> * the encoder is assigned to the given crtc
> * @encoder: encoder pointer
--
With best wishes
Dmitry
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