linux-kernel - Re: [PATCH v4 07/25] drm/msm/dpu: move resource allocation to CRTC

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Message-ID: <y2qtp2avw7hjkweh3svfwr6ytvg54lmhqiowfjeiufnyhxiryw@vb4mwnyi2ict>
Date: Fri, 20 Dec 2024 04:32:34 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc: Jessica Zhang <quic_jesszhan@...cinc.com>, 
	Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, David Airlie <airlied@...il.com>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, Simona Vetter <simona@...ll.ch>, 
	Simona Vetter <simona.vetter@...ll.ch>, quic_ebharadw@...cinc.com, linux-arm-msm@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	Rob Clark <robdclark@...omium.org>, Ville Syrjälä <ville.syrjala@...ux.intel.com>
Subject: Re: [PATCH v4 07/25] drm/msm/dpu: move resource allocation to CRTC

On Mon, Dec 16, 2024 at 05:47:50PM -0800, Abhinav Kumar wrote:
> 
> 
> On 12/16/2024 4:43 PM, Jessica Zhang wrote:
> > From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > 
> > All resource allocation is centered around the LMs. Then other blocks
> > (except DSCs) are allocated basing on the LMs that was selected, and LM
> > powers up the CRTC rather than the encoder.
> > 
> > Moreover if at some point the driver supports encoder cloning,
> > allocating resources from the encoder will be incorrect, as all clones
> > will have different encoder IDs, while LMs are to be shared by these
> > encoders.
> > 
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > [quic_abhinavk@...cinc.com: Refactored resource allocation for CDM]
> > Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> > [quic_jesszhan@...cinc.com: Changed to grabbing exising global state]
> > Signed-off-by: Jessica Zhang <quic_jesszhan@...cinc.com>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    |  86 ++++++++++
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 256 ++++++++++------------------
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |   8 +
> >   3 files changed, 181 insertions(+), 169 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > index 9f6ffd344693ecfb633095772a31ada5613345dc..186ed84f59f16997716fe216e635b8dce07a63a1 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > @@ -1182,6 +1182,78 @@ static bool dpu_crtc_needs_dirtyfb(struct drm_crtc_state *cstate)
> >   	return false;
> >   }
> 
> <snip>
> 
> > +static bool dpu_encoder_needs_dsc_merge(struct drm_encoder *drm_enc)
> >   {
> > -	struct dpu_crtc_state *cstate;
> > -	struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_ENC];
> > -	struct dpu_hw_blk *hw_lm[MAX_CHANNELS_PER_ENC];
> > -	struct dpu_hw_blk *hw_dspp[MAX_CHANNELS_PER_ENC];
> > -	int num_lm, num_ctl, num_dspp, i;
> > -
> > -	cstate = to_dpu_crtc_state(crtc_state);
> > -
> > -	memset(cstate->mixers, 0, sizeof(cstate->mixers));
> > -
> > -	num_ctl = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
> > -		drm_enc->crtc, DPU_HW_BLK_CTL, hw_ctl, ARRAY_SIZE(hw_ctl));
> > -	num_lm = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
> > -		drm_enc->crtc, DPU_HW_BLK_LM, hw_lm, ARRAY_SIZE(hw_lm));
> > -	num_dspp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
> > -		drm_enc->crtc, DPU_HW_BLK_DSPP, hw_dspp,
> > -		ARRAY_SIZE(hw_dspp));
> > +	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
> > +	u32 num_intf = 0;
> > +	u32 num_dsc = 0;
> > +	int i;
> > -	for (i = 0; i < num_lm; i++) {
> > -		int ctl_idx = (i < num_ctl) ? i : (num_ctl-1);
> > +	for (i = 0; i < MAX_PHYS_ENCODERS_PER_VIRTUAL; i++)
> > +		if (dpu_enc->phys_encs[i])
> > +			num_intf++;
> > -		cstate->mixers[i].hw_lm = to_dpu_hw_mixer(hw_lm[i]);
> > -		cstate->mixers[i].lm_ctl = to_dpu_hw_ctl(hw_ctl[ctl_idx]);
> > -		cstate->mixers[i].hw_dspp = i < num_dspp ? to_dpu_hw_dspp(hw_dspp[i]) : NULL;
> > -	}
> > +	/* We only support 2 DSC mode (with 2 LM and 1 INTF) */
> > +	if (dpu_enc->dsc)
> > +		num_dsc += 2;
> 
> As we requested in v3, can you please explain why we have num_dsc +=2
> instead of just num_dsc = 2? If we are hard-coding 2:2:1, this should be
> just num_dsc = 2.

I'll drop it while applying a first part of the series. Granted that
num_dsc is initialized to 0 few lines above, it should be fine.

If later there is a need to change the lane, it can be done in a
consequent patch.


-- 
With best wishes
Dmitry