On Tue, Mar 30, 2021 at 12:36 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > Quoting Saravana Kannan (2021-03-30 11:50:55) > > 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> > > --- > > Tested-by: Stephen Boyd <swboyd@xxxxxxxxxxxx> Thanks! > > > diff --git a/drivers/of/property.c b/drivers/of/property.c > > index 5036a362f52e..2bb3158c9e43 100644 > > --- a/drivers/of/property.c > > +++ b/drivers/of/property.c > > @@ -1225,6 +1230,8 @@ static struct device_node *parse_##fname(struct device_node *np, \ > > * @parse_prop.prop_name: Name of property holding a phandle value > > * @parse_prop.index: For properties holding a list of phandles, this is the > > * index into the list > > + * @optional: The property can be an optional dependency. > > This bit conflicted for me on linux-next today so I dropped it in favor > of 3915fed92365 ("of: property: Provide missing member description and > remove excess param"). Ah looks like a change went into DT git repo but not in driver-core yet. Yeah, dropping this bit is fine. Rob/Greg, I'll leave it to you to deal with the conflict? I can't send to DT because the fix needs to land in driver-core because of boot issues and I can't resolve the conflict in driver-core because the conflicting change isn't in driver-core yet. Thanks, Saravana
