Subject: [PATCH] USB: xhci: Fix a wrong calculation for beginning of
"first extended capability register"
From: Edward Shao <laface.tw@xxxxxxxxx>
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 support.
Signed-off-by: Edward Shao <laface.tw@xxxxxxxxx>
---
drivers/usb/host/xhci-ext-caps.h | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index ecc131c..073583f 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -101,9 +101,11 @@ static inline int xhci_find_next_cap_offset(void
__iomem *base, int ext_offset)
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);
+ ext_offset = 0;
+ }
else
/* Find the next extended capability */
next = XHCI_EXT_CAPS_NEXT(next);
--
1.6.5
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