Quoting Saravana Kannan (2021-05-19 18:27:50) > On Wed, May 19, 2021 at 5:25 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > > > This series is from discussion we had on reordering the device lists for > > drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put > > the aggregate device onto and then we probe the device once all the > > components are probed and call component_add(). The probe/remove hooks > > are where the bind/unbind calls go, and then a shutdown hook is added > > that can be used to shutdown the drm display pipeline at the right time. > > > > This works for me on my sc7180 board, but I'm currently struggling with > > the last patch where we migrate the msm driver. It runs into a runtime > > PM problem where the parent device isn't runtime PM enabled yet. I'm > > still trying to figure out a clean solution there. Moving runtime PM > > around breaks boot and I think that's because the power domain is off. > > > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > > Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> > > Cc: Rob Clark <robdclark@xxxxxxxxx> > > Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> > > Cc: Saravana Kannan <saravanak@xxxxxxxxxx> > > > > [1] https://lore.kernel.org/r/20210508074118.1621729-1-swboyd@xxxxxxxxxxxx > > > > I skimmed through the series and in general the idea is good, but I'm > not sure why each component user needs to be converted/"modern" before > it can make use of the benefits of this series. Why not just have > wrapper functions around the component ops that the new aggregate bus > driver can just call? That'll give all the existing component users > the new ability to use the new ops without having to have two > versions. The existing users can only have one or the other. Either use the ops structure or use the struct aggregate_driver. What benefits of this series are they not gaining? > That'll also allow us to do other improvements (I have some > in mind) that'll apply to all the component users instead of only the > converted ones. What do you have in mind? I didn't want to convert drivers over to the new way of doing things without making them consciously change their code. Otherwise I worry it will break things in random, subtle ways. The last patch, as I mentioned above in the cover, causes warnings because the display driver is enabling runtime PM in an odd spot as part of the bind callback of the aggregate/master. That should move out of there and into the msm_pdev driver that registers the aggregate from what I can tell.
