USB: xhci: Fix finding extended capabilities registers
According "5.3.6 Capability Parameters (HCCPARAMS)" of xHCI rev0.96 spec,
value of xECP register indicates a relative offset, in 32-bit words,
from Base to the beginning of the first extended capability.
The wrong calculation will cause BIOS handoff fail (not handoff from BIOS)
in some platform with BIOS USB legacy sup support.
Signed-off-by: Edward Shao <laface.tw@gmail.com>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index ecc131c..78c4eda 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -101,12 +101,15 @@
next = readl(base + ext_offset);
- if (ext_offset == XHCI_HCC_PARAMS_OFFSET)
+ if (ext_offset == XHCI_HCC_PARAMS_OFFSET) {
/* Find the first extended capability */
next = XHCI_HCC_EXT_CAPS(next);
- else
+ ext_offset = 0;
+ } else {
/* Find the next extended capability */
next = XHCI_EXT_CAPS_NEXT(next);
+ }
+
if (!next)
return 0;
/*