On Tue, May 26, 2020 at 12:05 AM Saravana Kannan <sarava...@google.com> wrote: > > When SYNC_STATE_ONLY support was added in commit 05ef983e0d65 ("driver > core: Add device link support for SYNC_STATE_ONLY flag"), > SYNC_STATE_ONLY links were treated similar to STATELESS links in terms > of not blocking consumer probe if the supplier hasn't probed yet. > > That caused a SYNC_STATE_ONLY device link's status to not get updated. > Since SYNC_STATE_ONLY device link is no longer useful once the > consumer probes, commit 21c27f06587d ("driver core: Fix > SYNC_STATE_ONLY device link implementation") addresses the status > update issue by deleting the SYNC_STATE_ONLY device link instead of > complicating the status update code. > > However, there are still some cases where we need to update the status > of a SYNC_STATE_ONLY device link. A SYNC_STATE_ONLY device link can > later get converted into a normal MANAGED device link when a normal > MANAGED device link is created between a supplier and consumer that > already have a SYNC_STATE_ONLY device link between them. If a > SYNC_STATE_ONLY device link's status isn't maintained correctly till > it's converted to a normal MANAGED device link, then the normal > MANAGED device link will end up with a wrong link status. This can > cause a warning stack trace[1] when the consumer device probes. > > This commit fixes the SYNC_STATE_ONLY device link status update issue > where it wouldn't transition correctly from DL_STATE_AVAILABLE to > DL_STATE_CONSUMER_PROBE. > > [1] - https://lore.kernel.org/lkml/20200522204120.3b3c9ed6@apollo/ > Fixes: 05ef983e0d65 ("driver core: Add device link support for > SYNC_STATE_ONLY flag") > Fixes: 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link > implementation") > Reported-by: Michael Walle <mich...@walle.cc> > Signed-off-by: Saravana Kannan <sarava...@google.com> > --- > Greg, > > I think this is the issue Michael ran into. I'd like him to test the fix > before it's pulled in. > > Michael, > > If you can test this on the branch you saw the issue in and give a > Tested-by if it works, that'd be great. > > Thanks, > Saravana > > drivers/base/core.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 791b7530599f..9511be3f9a32 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -687,11 +687,11 @@ int device_links_check_suppliers(struct device *dev) > device_links_write_lock(); > > list_for_each_entry(link, &dev->links.suppliers, c_node) { > - if (!(link->flags & DL_FLAG_MANAGED) || > - link->flags & DL_FLAG_SYNC_STATE_ONLY) > + if (!(link->flags & DL_FLAG_MANAGED)) > continue; > > - if (link->status != DL_STATE_AVAILABLE) { > + if (link->status != DL_STATE_AVAILABLE && > + !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) { > device_links_missing_supplier(dev); > ret = -EPROBE_DEFER; > break; > -- > 2.27.0.rc0.183.gde8f92d652-goog >
Adding stable@ that I forgot to add earlier. -Saravana