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EHCI: zero out QH transfer overlay in ehci_submit_async() 

ehci_submit_async() doesn't really zero out the QH transfer overlay (as the EHCI
specification suggests) which leads to the controller seeing the "token" field
as the previous call has left it, i.e.:
- if a timeout occured on the previous call (Active bit left as 1), controller
  incorrectly tries to complete a previous transaction on a newly programmed
  endpoint;
- if a halt occured on the previous call (Halted bit set to 1), controller just
  ignores the newly programmed TD(s) and the function then keeps returning error
  ad infinitum.

This turned out to be caused by the wrong orger of the arguments to the memset()
call in ehci_alloc(), so the allocated TDs weren't cleared either.

While at it, stop needlessly initializing the alternate next TD pointer in the
QH transfer overlay...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Remy Bohmer <linux@bohmer.net>
This commit is contained in:
Sergei Shtylyov 2010-06-28 22:44:49 +04:00 committed by Wolfgang Denk
parent 0d7f4abcf6
commit 9fb3b50857
1 changed files with 1 additions and 2 deletions
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3
drivers/usb/host/ehci-hcd.c
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@ -275,7 +275,7 @@ static void *ehci_alloc(size_t sz, size_t align)
return NULL;
}
memset(p, sz, 0);
memset(p, 0, sz);
return p;
}
@ -350,7 +350,6 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer,
(dev->parent->devnum << 16) | (0 << 8) | (0 << 0);
qh->qh_endpt2 = cpu_to_hc32(endpt);
qh->qh_overlay.qt_next = cpu_to_hc32(QT_NEXT_TERMINATE);
qh->qh_overlay.qt_altnext = cpu_to_hc32(QT_NEXT_TERMINATE);
td = NULL;
tdp = &qh->qh_overlay.qt_next;