Re: [Qemu-devel] USB PCI host bus adapter hot plug

[Gonglei (Arei)]

> >>> I noticed that QMP's "device_add usb-ehci,id=i2,bus=pci.0" fails on PCI
> >>> hotplug. The same for pci-ohci and this is because their initfn() do
> >>> "dc->hotpluggable   = false". So I removed those and now I can hotplug
> USB
> >>> hosts but none of them is able to actually work:
> >>>
> >>> address@hidden:~# echo 1 >/sys/bus/pci/rescan
> >>> [   41.143062] ohci-pci 0000:00:01.0: init err (c8700000 0000)
> >>> [   41.143133] ohci-pci 0000:00:01.0: can't start
> >>> [   41.143227] ohci-pci 0000:00:01.0: startup error -75
> >>> [   41.144202] ohci-pci 0000:00:01.0: init 0000:00:01.0 fail, -75
> >>>
> >>>
> >>> address@hidden:~# echo 1 >/sys/bus/pci/rescan
> >>> [   43.691067] ehci-pci 0000:00:01.0: can't setup: -110
> >>> [   43.692424] ehci-pci 0000:00:01.0: init 0000:00:01.0 fail, -110
> >>>
> >>>
> >>> Why is that? Is QEMU just missing some bits or there is some fundamental
> >>> issue which I just do not see? Thanks!
> >>>
> >> Cc'ing Gerd.
> >>
> >> Actually I have post a patch serials for supporting usb host adapter
> hotplugging,
> >> Which has been involved in Gerd's (the USB mantainer) usb-next tree. Please
> see:
> >> https://www.kraxel.org/cgit/qemu/log/?h=rebase/usb-next
> >>
> >> The function of usb host adapter hotplugging is ok. You are welcome to test
> it.
> >
> > It does not work for me though. The device appears in the system but the
> > driver fails to bring it up:
> >
> > address@hidden ~]# echo 1 >/sys/bus/pci/rescan
> >
> > [   43.482378] pci 0000:00:01.0: BAR 0: assigned [mem
> > 0x100a0000000-0x100a0000fff]
> > [   43.488851] ehci-pci 0000:00:01.0: EHCI Host Controller
> >
> > [   43.490153] ehci-pci 0000:00:01.0: new USB bus registered, assigned bus
> > number 1
> > [   43.504957] ehci-pci 0000:00:01.0: can't setup: -110
> >
> > [   43.505028] ehci-pci 0000:00:01.0: USB bus 1 deregistered
> >
> > [   43.507660] ehci-pci 0000:00:01.0: init 0000:00:01.0 fail, -110
> >
> > [   43.507808] ehci-pci: probe of 0000:00:01.0 failed with error -110
> >
> >
> >
> >> BTW, What's your guest os type?
> >
> > Fedora20/ppc64 or Ubuntu14/ppc64le.
> >
> > I tried your tree merged with
> > https://github.com/mdroth/qemu/tree/spapr-pci-hotplug-ppc-next-cleanup2
> >
> > I am adding PCIhotplug-on-PPC experts to the thread, may be they have
> ideas...
> 
> 
> More precise - this fails:
> 
> drivers/usb/host/ehci-hcd.c:
> 
> int ehci_handshake(struct ehci_hcd *ehci, void __iomem *ptr,
>                    u32 mask, u32 done, int usec)
> {
>         u32     result;
> 
>         do {
>                 result = ehci_readl(ehci, ptr);
>                 if (result == ~(u32)0)          /* card removed */
>                         return -ENODEV;
>                 result &= mask;
>                 if (result == done)
>                         return 0;
>                 udelay (1);
>                 usec--;
>         } while (usec > 0);
>         return -ETIMEDOUT; // <------------------
> }
> 
> --
> Alexey

Hi, Alexey. 

Does this work when you configure 
EHCI at the command line, not hotplugging?

BTW, I'm not familiar with PCIhotplug-on-PPC. Sorry for this.

Best regards,
-Gonglei