Re: [PATCH 1/3] drm/msm/dpu: Add DPU_INTF_DATABUS_WIDEN feature flag for DPU >= 5.0

[Dmitry Baryshkov]

On 14/06/2023 14:42, Marijn Suijten wrote:
> On 2023-06-13 18:57:11, Jessica Zhang wrote:
> > DPU 5.x+ supports a databus widen mode that allows more data to be sent
> > per pclk. Enable this feature flag on all relevant chipsets.
> >
> > Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 3 ++-
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 2 ++
> >   2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
> > index 36ba3f58dcdf..0be7bf0bfc41 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
> > @@ -103,7 +103,8 @@
> >   	(BIT(DPU_INTF_INPUT_CTRL) | \
> >   	 BIT(DPU_INTF_TE) | \
> >   	 BIT(DPU_INTF_STATUS_SUPPORTED) | \
> > -	 BIT(DPU_DATA_HCTL_EN))
> > +	 BIT(DPU_DATA_HCTL_EN) | \
> > +	 BIT(DPU_INTF_DATABUS_WIDEN))
>
> This doesn't work.  DPU 5.0.0 is SM8150, which has DSI 6G 2.3.  In the
> last patch for DSI you state and enable widebus for DSI 6G 2.5+ only,
> meaning DPU and DSI are now desynced, and the output is completely
> corrupted.
>
> Is the bound in dsi_host wrong, or do DPU and DSI need to communicate
> when widebus will be enabled, based on DPU && DSI supporting it?

I'd prefer to follow the second approach, as we did for DP. DPU asks the 
actual video output driver if widebus is to be enabled.

> - Marijn
>
> >   #define INTF_SC7280_MASK (INTF_SC7180_MASK | BIT(DPU_INTF_DATA_COMPRESS))
> >   
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> > index b860784ade72..b9939e00f5e0 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
> > @@ -182,6 +182,7 @@ enum {
> >    *                                  than video timing
> >    * @DPU_INTF_STATUS_SUPPORTED       INTF block has INTF_STATUS register
> >    * @DPU_INTF_DATA_COMPRESS          INTF block has DATA_COMPRESS register
> > + * @DPU_INTF_DATABUS_WIDEN          INTF block has DATABUS_WIDEN register
> >    * @DPU_INTF_MAX
> >    */
> >   enum {
> > @@ -190,6 +191,7 @@ enum {
> >   	DPU_DATA_HCTL_EN,
> >   	DPU_INTF_STATUS_SUPPORTED,
> >   	DPU_INTF_DATA_COMPRESS,
> > +	DPU_INTF_DATABUS_WIDEN,
> >   	DPU_INTF_MAX
> >   };
> >   
> >
> > --
> > 2.40.1

--
With best wishes
Dmitry