[RFC PATCH] drm/msm: lookup the ICC paths in both mdp5/dpu and mdss devices

[Dmitry Baryshkov]

On 05/08/2022 15:24, Marijn Suijten wrote:
> On 2022-08-05 14:56:30, Dmitry Baryshkov wrote:
>> The commit 6874f48bb8b0 ("drm/msm: make mdp5/dpu devices master
>> components") changed the MDP5 driver to look for the interconnect paths
>> in the MDSS device rather than in the MDP5 device itself. This was left
>> unnoticed since on my testing devices the interconnects probably didn't
>> reach the sync state.
>>
>> Rather than just using the MDP5 device for ICC path lookups for the MDP5
>> devices, introduce an additional helper to check both MDP5/DPU and MDSS
>> nodes. This will be helpful for the MDP5->DPU conversion, since the
>> driver will have to check both nodes.
>>
>> Fixes: 6874f48bb8b0 ("drm/msm: make mdp5/dpu devices master components")
>> Reported-by: Marijn Suijten <marijn.suijten at somainline.org>
>> Reported-by: Yassine Oudjana <y.oudjana at protonmail.com>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> 
> Tested-by: Marijn Suijten <marijn.suijten at somainline.org> # On sdm630
> 
> But I'm not sure about giving my Reviewed-by to this, as I'd rather
> *correct* the DT bindings for sdm630 and msm8996 to provide
> interconnects in the MDSS node unless there are strong reasons not to
> (and I don't consider "backwards compatibility" to be one, this binding
> "never even existed" if mdp5.txt is to be believed).

As a kind of a joke, I'd prefer to have interconnects in the mdp/dpu 
device node. In the end, the interconnects describe the path between the 
display controller and the DDR, not the path between the whole MDSS and DDR.

So, for next chipsets I'd vote to move icc to dpu/mdp node (and maybe 
even move existing inerconnects to the dpu node).

-- 
With best wishes
Dmitry