linux-kernel - Re: [PATCH] drm/msm/dpu: Bind pingpong block to intf on active ctls in cmd encoder

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Date:   Wed, 2 Feb 2022 10:48:50 +0100
From:   Marijn Suijten <marijn.suijten@...ainline.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     phone-devel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Martin Botka <martin.botka@...ainline.org>,
        Jami Kettunen <jami.kettunen@...ainline.org>,
        Pavel Dubrova <pashadubrova@...il.com>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Abhinav Kumar <abhinavk@...eaurora.org>,
        Zhen Lei <thunder.leizhen@...wei.com>,
        Bernard <bernard@...o.com>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/msm/dpu: Bind pingpong block to intf on active ctls
 in cmd encoder

On 2022-01-20 02:12:51, Dmitry Baryshkov wrote:
> On 22/12/2021 13:55, Marijn Suijten wrote:
> > As per the specification of DPU_CTL_ACTIVE_CFG the configuration of
> > active blocks should be proactively specified, and the pingpong block is
> > no different.
> > 
> > The downstream display driver [1] confirms this by also calling
> > bind_pingpong_blk on CTL_ACTIVE_CFG.  Note that this else-if is always
> > entered, as setup_intf_cfg - unlike this mainline dpu driver that
> > combines both behind the same function pointer - is left NULL in favour
> > of using setup_intf_cfg_v1 when CTL_ACTIVE_CFG is set.
> > 
> > This solves continuous timeouts on at least the Qualcomm sm6125 SoC:
> > 
> >      [drm:dpu_encoder_frame_done_timeout:2091] [dpu error]enc31 frame done timeout
> >      [drm:_dpu_encoder_phys_cmd_handle_ppdone_timeout.isra.0] *ERROR* id:31 pp:0 kickoff timeout 0 cnt 1 koff_cnt 1
> >      [drm:dpu_encoder_phys_cmd_prepare_for_kickoff] *ERROR* failed wait_for_idle: id:31 ret:-110 pp:0
> > 
> > In the same way this pingpong block should also be unbound followed by
> > an interface flush when the encoder is disabled, according to the
> > downstream display driver [2].
> > 
> > [1]: https://source.codeaurora.org/quic/la/platform/vendor/opensource/display-drivers/tree/msm/sde/sde_encoder_phys_cmd.c?h=LA.UM.9.16.r1-08500-MANNAR.0#n167
> > [2]: https://source.codeaurora.org/quic/la/platform/vendor/opensource/display-drivers/tree/msm/sde/sde_encoder.c?h=LA.UM.9.16.r1-08500-MANNAR.0#n2986
> > 
> > Signed-off-by: Marijn Suijten <marijn.suijten@...ainline.org>
> > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> 
> > ---
> >   .../drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c  | 21 +++++++++++++++++++
> >   1 file changed, 21 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
> > index 8e433af7aea4..e0e08a874f07 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
> > @@ -71,6 +71,13 @@ static void _dpu_encoder_phys_cmd_update_intf_cfg(
> >   	intf_cfg.stream_sel = cmd_enc->stream_sel;
> >   	intf_cfg.mode_3d = dpu_encoder_helper_get_3d_blend_mode(phys_enc);
> >   	ctl->ops.setup_intf_cfg(ctl, &intf_cfg);
> > +
> > +	/* setup which pp blk will connect to this intf */
> > +	if (test_bit(DPU_CTL_ACTIVE_CFG, &ctl->caps->features) && phys_enc->hw_intf->ops.bind_pingpong_blk)
> 
> Nit: here we bind all interfaces, but later we unbind only master. Is 
> this correct?

Not sure: it seems downstream only calls
_sde/dpu_encoder_phys_cmd_update_intf_cfg when it is _not_ a ppsplit
slave, which appears to be very similar to being the master (both check
for ENC_ROLE_SLAVE but ppsplit also checks RM topology support for
ppsplit).  Should we do this too before calling
_dpu_encoder_phys_cmd_update_intf_cfg?

- Marijn

> > +		phys_enc->hw_intf->ops.bind_pingpong_blk(
> > +				phys_enc->hw_intf,
> > +				true,
> > +				phys_enc->hw_pp->idx);
> >   }
> >   
> >   static void dpu_encoder_phys_cmd_pp_tx_done_irq(void *arg, int irq_idx)
> > @@ -507,6 +514,7 @@ static void dpu_encoder_phys_cmd_disable(struct dpu_encoder_phys *phys_enc)
> >   {
> >   	struct dpu_encoder_phys_cmd *cmd_enc =
> >   		to_dpu_encoder_phys_cmd(phys_enc);
> > +	struct dpu_hw_ctl *ctl;
> >   
> >   	if (!phys_enc->hw_pp) {
> >   		DPU_ERROR("invalid encoder\n");
> > @@ -523,6 +531,19 @@ static void dpu_encoder_phys_cmd_disable(struct dpu_encoder_phys *phys_enc)
> >   
> >   	if (phys_enc->hw_pp->ops.enable_tearcheck)
> >   		phys_enc->hw_pp->ops.enable_tearcheck(phys_enc->hw_pp, false);
> > +
> > +	if (dpu_encoder_phys_cmd_is_master(phys_enc)) {
> > +		if (phys_enc->hw_intf->ops.bind_pingpong_blk) {
> > +			phys_enc->hw_intf->ops.bind_pingpong_blk(
> > +					phys_enc->hw_intf,
> > +					false,
> > +					phys_enc->hw_pp->idx);
> > +
> > +			ctl = phys_enc->hw_ctl;
> > +			ctl->ops.update_pending_flush_intf(ctl, phys_enc->intf_idx);
> > +		}
> > +	}
> > +
> >   	phys_enc->enable_state = DPU_ENC_DISABLED;
> >   }
> >   
> 
> 
> -- 
> With best wishes
> Dmitry