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libpayload: Handle underruns in UHCI interrupt queues 

If usb_poll() isn't called fast enough, the UHCI controller marks an
underrun interrupt queue as done (terminating the queue at the head).
We can recover from this situation, when usb_poll() gets called again,
and the queue is processed.

Change-Id: Id56c9df44d6dbd53cd30ad89dfb5bf5977799829
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1898
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
This commit is contained in:
Nico Huber 2012-11-20 17:49:00 +01:00 committed by Patrick Georgi
parent ce407e470d
commit 8c4d2f36a3
1 changed files with 5 additions and 0 deletions
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5
payloads/libpayload/drivers/usb/uhci.c
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@ -590,6 +590,11 @@ uhci_poll_intr_queue (void *q_)
q->lastread = (q->lastread + 1) % q->total;
return &q->data[current*q->reqsize];
}
/* reset queue if we fully processed it after underrun */
else if (q->qh->elementlinkptr & FLISTP_TERMINATE) {
usb_debug("resetting underrun uhci interrupt queue.\n");
q->qh->elementlinkptr = virt_to_phys(q->tds + q->lastread);
}
return NULL;
}