ChangeSet 1.1843.4.2, 2004/08/24 11:38:47-07:00, [EMAIL PROTECTED]
[PATCH] USB: Set QH bit in UHCI framelist entries
This patch fixes the error in the UHCI driver found by Stuart Hayes. It
adds the UHCI_PTR_QH bit into the initial entries stored in the hardware
framelist. It's not entirely clear how the driver ever managed to work
with these bits not set; apparently by coincidence the QH entries
resembled TD entries sufficiently closely to fool the hardware.
On Tue, 10 Aug 2004 [EMAIL PROTECTED] wrote:
> Never mind, I figured it out. It looks like the uhci-hcd driver
> doesn't add a "| UHCI_PTR_QH" to the pointers that it puts
> in the frame list. This causes the ICH to think that the frame list
> is pointing to a bunch of TDs instead of QHs for purposes of
> checking for TD errors. I can only assume that the ICH
> is actually treating the frame list entries as QH pointers in spite
> of that bit not being set when it is actually executing the
> schedule, or else I don't think it would work generally.
>
> I guess the high addresses were just making the QH look like an
> invalid TD instead of a valid TD... not sure exactly what the ICH
> is checking for!
Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
drivers/usb/host/uhci-hcd.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletion(-)
diff -Nru a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
--- a/drivers/usb/host/uhci-hcd.c 2004-08-26 16:43:45 -07:00
+++ b/drivers/usb/host/uhci-hcd.c 2004-08-26 16:43:45 -07:00
@@ -2254,7 +2254,8 @@
irq = 7;
/* Only place we don't use the frame list routines */
- uhci->fl->frame[i] = cpu_to_le32(uhci->skelqh[irq]->dma_handle);
+ uhci->fl->frame[i] = UHCI_PTR_QH |
+ cpu_to_le32(uhci->skelqh[irq]->dma_handle);
}
/*
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