Messages in this thread | | | From | Saravana Kannan <> | Date | Tue, 26 May 2020 14:45:30 -0700 | Subject | Re: [PATCH v2] driver core: Update device link status correctly for SYNC_STATE_ONLY links |
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On Tue, May 26, 2020 at 2:13 PM Michael Walle <michael@walle.cc> wrote: > > Am 2020-05-26 21:43, schrieb Saravana Kannan: > > 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. This is because 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 successfully. > > > > This commit fixes the SYNC_STATE_ONLY device link status update issue > > where it wouldn't transition correctly from DL_STATE_DORMANT or > > DL_STATE_AVAILABLE to DL_STATE_CONSUMER_PROBE. It also resets the > > status > > back to DL_STATE_DORMANT or DL_STATE_AVAILABLE if the consumer probe > > fails. > > > > [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 <michael@walle.cc> > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > --- > > > > v1->v2: > > - Added code to "revert" the link status if consumer probe fails > > > > 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. > > with v2 I'm triggering the > WARN_ON(!(link->status & DL_FLAG_SYNC_STATE_ONLY)); > in __device_links_no_driver().
Thanks for the logs! The WARNING is due to a dump typo in this line. I should be checking link->flags, not link->status here. I'll send out a v3, but you can test with this change too.
-Saravana
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