[PATCH 4/6] PCI: Fix Intel generic reset quirk class code check

[Bjorn Helgaas <bhelgaas@google.com>]

We checked for "dev->class == PCI_CLASS_SERIAL_USB", but dev->class
contains the entire three-byte base class/sub-class/interface, while
PCI_CLASS_SERIAL_USB is only the two-byte base class/sub-class.

This error meant that we used the Intel device-specific reset on devices
with class code 0x000c03 instead of those with class code 0x0c03xx.
0x000c03 is a reserved value in the 0x00 backwards compatibility base class
and shouldn't match any devices, so I think reset_intel_generic_dev()
always failed.

Shift dev->class to discard the interface byte before comparing with
PCI_CLASS_SERIAL_USB.

Fixes: aeb30016fec3 ("PCI: add Intel USB specific reset method")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Dexuan Cui <dexuan.cui@intel.com>
CC: Yu Zhao <yu.zhao@intel.com>
---
 drivers/pci/quirks.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 8bc60c2..356a401 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3358,7 +3358,7 @@ static int reset_intel_generic_dev(struct pci_dev *dev, int probe)
 	int pos;
 
 	/* only implement PCI_CLASS_SERIAL_USB at present */
-	if (dev->class == PCI_CLASS_SERIAL_USB) {
+	if ((dev->class >> 8) == PCI_CLASS_SERIAL_USB) {
 		pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
 		if (!pos)
 			return -ENOTTY;

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