Re: [RFC] xhci: Fix BIOS handoff failure on some Intel systems.

[Sarah Sharp <sarah.a.sharp@linux.intel.com>]

On Wed, Feb 08, 2012 at 04:11:37PM +0100, Oliver Neukum wrote:
> Am Mittwoch, 8. Februar 2012, 00:31:18 schrieb Sarah Sharp:
> > The downside is that the xHCI BIOS handoff mechanism will fail because
> > memory mapped I/O is not enabled for the disabled PCI device.  Make the
> > xHCI quirk handler call pci_enable_device() to re-enable MMIO, and call
> > pci_disable_device() once it's done with the BIOS handoff.  This will
> > balance the ref counts in the PCI core.  When the xHCI PCI probe is
> > called, usb_hcd_pci_probe() will call pci_enable_device() again.
> > 
> > Also add some debugging to the xHCI quirk failure paths, so we can pin
> > point the problem when a user says their xHCI PCI quirk function fails.
> > 
> > Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
> > ---
> > 
> > Hi Oliver,
> > 
> > What about this approach instead?  This means the PCI quirk sequence
> > doesn't change, and the xHCI ports are still switched over before the
> > EHCI PCI probe starts.  With your original patch, the ports could be
> > switched over after the EHCI driver has already started to enumerate
> > devices.
> > 
> > Can you test and make sure this fixes the issue on your test systems?
> 
> I've tested it and it works. Are you sure it is safe to enable a PCI device
> at that point? If so, your patch is better than mine.

Jesse Barnes told me it's fine over IRC, so I'm just going to send this
off, with your Tested-by line.

Thanks,
Sarah Sharp