Hi, On Thu, Apr 7, 2022 at 4:36 PM Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote: > > The ps8640 driver looks 'working by coincidence'. It calls > dp_aux_populate, then immediately after the function returns it checks > for the panel. If panel-edp is built as a module, the probe might fail > easily. > The anx7625 driver has the same kind of issue. The DP AUX bus is > populated from the probe() and after some additional work the panel is > being checked. > This design is fragile and from my quick glance it can break (or be > broken) too easy. It reminds me of our drm msm 'probe' loops > preventing the device to boot completely if the dsi bridge/panel could > not be probed in time. I did spend some time thinking about this, at least for ps8640. I believe that as long as the panel's probe isn't asynchronous. Basically if the panel isn't ready then ps8640 should return and we'll retry later. I do remember the probe loops that we used to have with msm and I don't _think_ this would trigger it. That being said, if we need to separate out the AUX bus into a sub-device like we did in sn65dsi86 we certainly could. -Doug
