Re: Null Pointer BUG in uhci_hcd

Alan Stern
2009-07-07T19:21:20Z

On Tue, 7 Jul 2009, Michael S. Zick wrote:

> On Tue July 7 2009, Alan Stern wrote:
> > On Tue, 7 Jul 2009, Michael S. Zick wrote:
> >
> > > > It looks like there's a serious problem in your UHCI hardware.
> > > > According to the log you posted, it's not working at all.
> > > >
> > >
> > > I am using the x86-generic drivers - -
> >
> > Not a problem with the drivers, a problem in the hardware.
> >
>
> Or hardware that works as the manufacturer intended, but differently
> than expected. Same difference as "broken" when compared to "standard".

No, hardware that doesn't work at all. As in "all reads return
0xffffffff" -- that's just a guess but something like it would account
for what you saw.

For more information enable CONFIG_USB_DEBUG and CONFIG_DEBUG_FS, then
see what's sitting in the usb/uhci/* files in debugfs.

> Let me see if I can find it again;
> 1106:3038 translates to: PCI_DEVICE_ID_VIA_82C586_2
> 1106:3104 translates to: PCI_DEVICE_ID_VIA_8235_USB_2
>
> The first appears in (this device is the UHCI hub in the CX700 chipset):
> arch/powerpc/platforms/85xx/mpc85xx_cds.c: case PCI_DEVICE_ID_VIA_82C586_2:
> arch/mips/pci/fixup-lm2e.c:DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_2,
> include/linux/pci_ids.h:#define PCI_DEVICE_ID_VIA_82C586_2 0x3038

Those are simple interrupt routing fixups. Not related.

> The second appears in:
> include/linux/pci_ids.h:#define PCI_DEVICE_ID_VIA_8235_USB_2 0x3104
> <Hmm... Dead? Not used? Never used? Source padding?>

Probably never used.

Alan Stern