Re: [PATCH] usb: pci-quirks: do not access OHCI_FMINTERVAL register on ULI hw

From: Alan Stern
Date: Thu May 29 2014 - 11:44:21 EST


On Thu, 29 May 2014, Nikita Yushchenko wrote:

> 29.05.2014 18:42, One Thousand Gnomes ÐÐÑÐÑ:
> >> I don't know how linux usb subsystem should behave against such
> >> "half-existing" hardware. Perhaps hanging is not the best idea...
> >> but maybe it should be fixed elsewhere, e.g. by masking non-wired
> >> devices in platform PCI setup. Perhaps controlled by some device-tree
> >> key.
> >
> > Does it have a unique svid/sdid set for the platform - if so you could
> > just blacklist that combination of vid/did/svid/sdid.
>
> Unfortunately vid/did/svid/sdid come from ULI 1553 southbridge chip,
> that is used by other hardware as well. AFAIK it is still being
> manufactured, and could appear in PCs or laptops.

> > It would help to print the value of fminterval.
> > And here to print the value obtained by the readl().
>
> I've checked these... all values read as 0xffffffff - which does not
> look correct

You could have the platform setup code read one of those hardware
registers, such as FMINTERVAL. If it obtains 0xffffffff, don't
register the OHCI controller as a platform device.

Alan Stern

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