drm/msm/dpu: tweaks for better hardware resources allocation

[PATCH 04/11] drm/msm/dpu: allow using lm mixer base stage

Posted by Arnaud Vrac 2 years, 8 months ago

The dpu backend already handles applying alpha to the base stage, so we
can use it to render the bottom plane in all cases. This allows mixing
one additional plane with the hardware mixer.

Signed-off-by: Arnaud Vrac <avrac@freebox.fr>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
index 14b5cfe306113..148921ed62f85 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
@@ -881,7 +881,7 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
 	r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
 	r_pipe->sspp = NULL;
 
-	pstate->stage = DPU_STAGE_0 + pstate->base.normalized_zpos;
+	pstate->stage = DPU_STAGE_BASE + pstate->base.normalized_zpos;
 	if (pstate->stage >= pdpu->catalog->caps->max_mixer_blendstages) {
 		DPU_ERROR("> %d plane stages assigned\n",
 			  pdpu->catalog->caps->max_mixer_blendstages - DPU_STAGE_0);

-- 
2.40.0

Re: [PATCH 04/11] drm/msm/dpu: allow using lm mixer base stage

Posted by Dmitry Baryshkov 2 years, 8 months ago

On 19/04/2023 17:41, Arnaud Vrac wrote:
> The dpu backend already handles applying alpha to the base stage, so we
> can use it to render the bottom plane in all cases. This allows mixing
> one additional plane with the hardware mixer.
> 
> Signed-off-by: Arnaud Vrac <avrac@freebox.fr>

This might require additional changes. First, for the STAGE_BASE pipe 
in the source split mode (iow using two LMs) should programmed with 
respect to the right LM's x offset (rather than usual left top-left LM). 
See  mdss_mdp_pipe_position_update().

Also this might need some interaction with CTL_MIXER_BORDER_OUT being 
set or not. If I remember correctly, if there bottom plane is not 
fullscreen or if there are no planes at all, we should set 
CTL_MIXER_BORDER_OUT (which takes STAGE_BASE) and start assigning them 
from STAGE0. If not, we can use STAGE_BASE.

> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> index 14b5cfe306113..148921ed62f85 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> @@ -881,7 +881,7 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
>   	r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
>   	r_pipe->sspp = NULL;
>   
> -	pstate->stage = DPU_STAGE_0 + pstate->base.normalized_zpos;
> +	pstate->stage = DPU_STAGE_BASE + pstate->base.normalized_zpos;
>   	if (pstate->stage >= pdpu->catalog->caps->max_mixer_blendstages) {
>   		DPU_ERROR("> %d plane stages assigned\n",
>   			  pdpu->catalog->caps->max_mixer_blendstages - DPU_STAGE_0);
> 

-- 
With best wishes
Dmitry

Re: [PATCH 04/11] drm/msm/dpu: allow using lm mixer base stage

Posted by Arnaud Vrac 2 years, 8 months ago

Le jeu. 20 avr. 2023 à 00:43, Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> a écrit :
>
> On 19/04/2023 17:41, Arnaud Vrac wrote:
> > The dpu backend already handles applying alpha to the base stage, so we
> > can use it to render the bottom plane in all cases. This allows mixing
> > one additional plane with the hardware mixer.
> >
> > Signed-off-by: Arnaud Vrac <avrac@freebox.fr>
>
> This might require additional changes. First, for the STAGE_BASE pipe
> in the source split mode (iow using two LMs) should programmed with
> respect to the right LM's x offset (rather than usual left top-left LM).
> See  mdss_mdp_pipe_position_update().

Ok, I did test with 2 LMs and it seems to be working, I'll investigate.

>
> Also this might need some interaction with CTL_MIXER_BORDER_OUT being
> set or not. If I remember correctly, if there bottom plane is not
> fullscreen or if there are no planes at all, we should set
> CTL_MIXER_BORDER_OUT (which takes STAGE_BASE) and start assigning them
> from STAGE0. If not, we can use STAGE_BASE.

I also tested with both fullscreen and non-fullscreen primary plane,
and no plane. I'll check this.

>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> > index 14b5cfe306113..148921ed62f85 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> > @@ -881,7 +881,7 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
> >       r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
> >       r_pipe->sspp = NULL;
> >
> > -     pstate->stage = DPU_STAGE_0 + pstate->base.normalized_zpos;
> > +     pstate->stage = DPU_STAGE_BASE + pstate->base.normalized_zpos;
> >       if (pstate->stage >= pdpu->catalog->caps->max_mixer_blendstages) {
> >               DPU_ERROR("> %d plane stages assigned\n",
> >                         pdpu->catalog->caps->max_mixer_blendstages - DPU_STAGE_0);
> >
>
> --
> With best wishes
> Dmitry
>

Re: [PATCH 04/11] drm/msm/dpu: allow using lm mixer base stage

Posted by Dmitry Baryshkov 2 years, 8 months ago

On 20/04/2023 10:26, Arnaud Vrac wrote:
> Le jeu. 20 avr. 2023 à 00:43, Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> a écrit :
>>
>> On 19/04/2023 17:41, Arnaud Vrac wrote:
>>> The dpu backend already handles applying alpha to the base stage, so we
>>> can use it to render the bottom plane in all cases. This allows mixing
>>> one additional plane with the hardware mixer.
>>>
>>> Signed-off-by: Arnaud Vrac <avrac@freebox.fr>
>>
>> This might require additional changes. First, for the STAGE_BASE pipe
>> in the source split mode (iow using two LMs) should programmed with
>> respect to the right LM's x offset (rather than usual left top-left LM).
>> See  mdss_mdp_pipe_position_update().
> 
> Ok, I did test with 2 LMs and it seems to be working, I'll investigate.

The only reference I have here is the fbdev driver, see [1]. The newer 
SDE driver doesn't handle STAGE_BASE vs STAGE0 (and DPU inherited that 
design). Maybe this got fixed in hw at some point.

[1] 
https://git.codelinaro.org/clo/la/kernel/msm-4.19/-/blob/LE.UM.4.4.1.r2-17500-QRB5165.0/drivers/video/fbdev/msm/mdss_mdp_pipe.c#L1789

I think, it only concerns the src_split + multirect cases, where the 
rectangle base point is on the right LM.

> 
>>
>> Also this might need some interaction with CTL_MIXER_BORDER_OUT being
>> set or not. If I remember correctly, if there bottom plane is not
>> fullscreen or if there are no planes at all, we should set
>> CTL_MIXER_BORDER_OUT (which takes STAGE_BASE) and start assigning them
>> from STAGE0. If not, we can use STAGE_BASE.
> 
> I also tested with both fullscreen and non-fullscreen primary plane,
> and no plane. I'll check this.

Yes, the DPU driver always enables the MIXER_BORDER_OUT.

> 
>>
>>> ---
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
>>> index 14b5cfe306113..148921ed62f85 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
>>> @@ -881,7 +881,7 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
>>>        r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
>>>        r_pipe->sspp = NULL;
>>>
>>> -     pstate->stage = DPU_STAGE_0 + pstate->base.normalized_zpos;
>>> +     pstate->stage = DPU_STAGE_BASE + pstate->base.normalized_zpos;
>>>        if (pstate->stage >= pdpu->catalog->caps->max_mixer_blendstages) {
>>>                DPU_ERROR("> %d plane stages assigned\n",
>>>                          pdpu->catalog->caps->max_mixer_blendstages - DPU_STAGE_0);
>>>
>>
>> --
>> With best wishes
>> Dmitry
>>

-- 
With best wishes
Dmitry