Re: [PATCH v1 0/5] Enable fw_devlink=on by default

From: Saravana Kannan
Date: Thu Jan 07 2021 - 16:55:04 EST


On Thu, Jan 7, 2021 at 12:04 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Dec 17, 2020 at 07:16:58PM -0800, Saravana Kannan wrote:
> > As discussed in LPC 2020, cyclic dependencies in firmware that couldn't
> > be broken using logic was one of the last remaining reasons
> > fw_devlink=on couldn't be set by default.
> >
> > This series changes fw_devlink so that when a cyclic dependency is found
> > in firmware, the links between those devices fallback to permissive mode
> > behavior. This way, the rest of the system still benefits from
> > fw_devlink, but the ambiguous cases fallback to permissive mode.
> >
> > Setting fw_devlink=on by default brings a bunch of benefits (currently,
> > only for systems with device tree firmware):
> > * Significantly cuts down deferred probes.
> > * Device probe is effectively attempted in graph order.
> > * Makes it much easier to load drivers as modules without having to
> > worry about functional dependencies between modules (depmod is still
> > needed for symbol dependencies).
> >
> > Greg/Rafael,
> >
> > Can we get this pulled into 5.11-rc1 or -rc2 soon please? I expect to
> > see some issues due to device drivers that aren't following best
> > practices (they don't expose the device to driver core). Want to
> > identify those early on and try to have them fixed before 5.11 release.
> > See [1] for an example of such a case.
>
> Now queued up in my tree, will show up in linux-next in a few days,
> let's see what breaks! :)
>
> And it is scheduled for 5.12-rc1, not 5.11, sorry.

Thanks. Not too worried about the actual version. I just want things
to start breaking as soon as possible if they are going to break.

-Saravana