Re: Missing USB XHCI and EHCI reset for kexec

[stefani]

Zitat von Benjamin Herrenschmidt <benh@xxxxxxxxxxx>:

> On Sun, 2014-04-13 at 21:22 +0200, Stefani Seibold wrote:
> > When executing a kexec kernel on a PowerPC board the new started kernel
> > will not find already enumerated USB devices due a missing reset on the
> > USB bus.
> >
> > As a work around a
> >
> > echo 1 >/sys/bus/pci/drivers/[ex]hci-pci/BUS-ADDRESS-OF-THE-HCD/reset
> >
> > will solve this. But this is far from beauty.
> >
> > My latest kernel without this issue was for EHCI kernel 2.6.39 and for
> > XHCI kernel 3.4, but i have no idea when exactly this behavior was
> > introduced.
> >
> > For X86 all is fine.
>
> I don't know about EHCI specifically but this is a known issue with
> XHCI, I observe similar issues on other powerpc platforms (servers)
> and this isn't architecture specific (looks more like actualy xhc
> implementation specific).
>
> Thadeu Cascardo (on CC) has been the one investigating that on our side,
> he might have more to add including patches.

I have now a kernel 3.14 dmesg log of the problem. After a kexec the  
kexeced 3.14 kernel shows:

[    1.170029] xhci_hcd 0001:03:00.0: xHCI Host Controller
[    1.175306] xhci_hcd 0001:03:00.0: new USB bus registered, assigned  
bus number 1
[    1.212561] xhci_hcd 0001:03:00.0: Host not halted after 16000  
microseconds.
[    1.219621] xhci_hcd 0001:03:00.0: can't setup: -110
[    1.224597] xhci_hcd 0001:03:00.0: USB bus 1 deregistered
[    1.230021] xhci_hcd 0001:03:00.0: init 0001:03:00.0 fail, -110
[    1.235955] xhci_hcd: probe of 0001:03:00.0 failed with error -110

Any idea?

- Stefani


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