tree a027880db74375f5dabd47026cc5cc7eb1e877e5
parent 444ce9d44d00969479aa1d2675f305a779369194
author Sarah Sharp <sarah.a.sharp@linux.intel.com> 1375981714 -0700
committer Sarah Sharp <sarah.a.sharp@linux.intel.com> 1375982442 -0700

xhci-plat: Don't enable legacy PCI interrupts.

The xHCI platform driver calls into usb_add_hcd to register the irq for
its platform device.  It does not want the xHCI generic driver to
register an interrupt for it at all.  The original code did that by
setting the XHCI_BROKEN_MSI quirk, which tells the xHCI driver to not
enable MSI or MSI-X for a PCI host.

Unfortunately, if CONFIG_PCI is enabled, and CONFIG_USB_DW3 is enabled,
the xHCI generic driver will attempt to register a legacy PCI interrupt
for the xHCI platform device in xhci_try_enable_msi().  This will result
in a bogus irq being registered, since the underlying device is a
platform_device, not a pci_device, and thus the pci_device->irq pointer
will be bogus.

Add a new quirk, XHCI_PLAT, so that the xHCI generic driver can
distinguish between a PCI device that can't handle MSI or MSI-X, and a
platform device that should not have its interrupts touched at all.
This quirk may be useful in the future, in case other corner cases like
this arise.

This patch should be backported to kernels as old as 3.9, that
contain the commit 00eed9c814cb8f281be6f0f5d8f45025dc0a97eb "USB: xhci:
correctly enable interrupts".

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: Yu Y Wang <yu.y.wang@intel.com>
Cc: stable@vger.kernel.org