Hi everyone, On Tue, 7 Dec 2021 at 09:37, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > On 9/5/21 6:23 PM, houlong wei wrote: > > Hi Ezequiel, > > > > Thank you for your attention to this series of patches. I answer partial of your questions below. > > Regards, > > Houlong > > > > On Sat, 2021-09-04 at 20:34 +0800, Ezequiel Garcia wrote: > >> Hi Eizan, > >> > >> Sorry for seeing this series so late. > >> > >> On Wed, 25 Aug 2021 at 03:35, Eizan Miyamoto <eizan@xxxxxxxxxxxx> > >> wrote: > >>> > >>> Broadly, this patch (1) adds a driver for various MTK MDP > >>> components to > >>> go alongside the main MTK MDP driver, and (2) hooks them all > >>> together > >>> using the component framework. > >>> > >>> (1) Up until now, the MTK MDP driver controls 8 devices in the > >>> device > >>> tree on its own. When running tests for the hardware video decoder, > >>> we > >>> found that the iommus and LARBs were not being properly configured. > >> > >> Why were not being properly configured? What was the problem? > >> Why not fixing that instead? > >> > >> Does this mean the driver is currently broken and unusable? > > > > This series of patches are supplements to another series, please refer > > to > > https://patchwork.kernel.org/project/linux-mediatek/list/?series=515129c > > , which add device link between the mtk-iommu consumer and the mtk-larb > > devices. Without that series of patches, the mtk-mdp driver can work > > well so far. > > But with that series, it seems the device link only can be established > > for the device which is registered as a platform driver. That's why > > Eizan adds this series of patches to make all mdp components to be > > registered as platform drivers. > > Hold on, so this means that if that iommu device-link series is merged, > then the mtk-mdp driver breaks? I posted a PR for that iommu series, but > I've just withdrawn that PR until this issue is clarified. > > Is it only mtk-mdp that is affected by this iommu device-link series, or > others as well? > Like I said before, I think it's a mistake to introduce the component framework in V4L2. This whole idea looks like a hack to me. If we merge this, then we validate using the component framework as a way to avoid fixing things properly. Regards, Ezequiel