Messages in this thread | | | Date | Sun, 1 Jan 2012 11:17:52 -0500 (EST) | From | Alan Stern <> | Subject | Re: loading firmware while usermodehelper disabled. |
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On Sun, 1 Jan 2012, Oliver Neukum wrote:
> Am Sonntag, 1. Januar 2012, 03:21:45 schrieb Alan Stern: > > On Sat, 31 Dec 2011, Oliver Neukum wrote: > > > > We are definitely going through do_unbind_rebind(). But I don't think > > > it matters why we got there. We seem to be calling probe() too early. > > > And we need to guarantee that a driver can request firmware in probe() > > > > > > So something has changed in the resume code path further up. > > > > For at least a year and a half, it has been true that rebinding takes > > Yes, so I don't understand why we haven't been hitting this issue > all that time.
Perhaps if Matthew compared logs from an old and a new system with appropriate debugging options configured, something might show up.
> > place during the complete phase of system resume. Clearly that is too > > early to load firmware. When do you think we should do it instead? > > I think we ought to delay until right after user space is unfrozen. > The devices are gone anyway, so we lose nothing but have the ability > to call helpers.
That's true. But doing it will be a nuisance. The nice thing about the current situation is that the driver core automatically iterates over all interfaces.
> > And how should we keep track of which interfaces need rebinding? > > I guess this calls for a brute force approach. We can kick khubd and have > it walk all busses checking for needs_binding.
Ugh. At a minimum, let's use a different process, not khubd.
As Linus pointed out, the real problem here is the firmware loader. The way it is now, a driver can't always depend on the data being available, even during a normal boot. It ought to use an asynchronous approach; then none of these problems would arise.
Alan Stern
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