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

[Marijn Suijten]

On 2023-06-14 15:01:59, Dmitry Baryshkov wrote:
> 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 at quicinc.com>
> >> ---
> >>   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.

Tested this on SM8350 which actually has DSI 2.5, and it is also
corrupted with this series so something else on this series might be
broken.

> > 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.

Doesn't it seem very strange that DPU 5.x+ comes with a widebus feature,
but the DSI does not until two revisions later?  Or is this available on
every interface, but only for a different (probably DP) encoder block?

- Marijn