On Tue, Mar 30, 2021 at 11:50:55AM -0700, Saravana Kannan wrote: > remote-endpoint property seems to always come in pairs where two devices > point to each other. So, we can't really tell from DT if there is a > functional probe order dependency between these two devices. > > However, there can be other dependencies between two devices that point > to each other with remote-endpoint. This non-remote-endpoint dependency > combined with one of the remote-endpoint dependency can lead to a cyclic > dependency[1]. > > To avoid this cyclic dependency from incorrectly blocking probes, > fw_devlink needs to be made aware of remote-endpoint dependencies even > though remote-endpoint dependencies by themselves won't affect probe > ordering (because fw_devlink will see the cyclic dependency between > remote-endpoint devices and ignore the dependencies that cause the > cycle). > > Also, if a device ever needs to know if a non-probe-blocking > remote-endpoint has finished probing, it can now use the sync_state() to > figure it out. > > [1] - https://lore.kernel.org/lkml/CAGETcx9Snf23wrXqjDhJiTok9M3GcoVYDSyNYSMj9QnSRrA=cA@xxxxxxxxxxxxxx/#t > Fixes: ea718c699055 ("Revert "Revert "driver core: Set fw_devlink=on by default""") > Reported-by: Stephen Boyd <swboyd@xxxxxxxxxxxx> > Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx> > --- > Rob/Greg, > > This needs to go into driver-core due to the Fixes. Now picked up, thanks. greg k-h
