This patch attempts to update the imx21-hcd driver to the current
standard for the isochronous API. Firstly, urb->start_frame should
always be set by the driver; it is not an input parameter. Secondly,
the URB_ISO_ASAP flag matters only when an URB is submitted to a
stream that has gotten an underrun. It causes the URB to be scheduled
for the next available slot in the future, rather than the earliest
unused (and expired) slot.
Unfortunately, I don't have any way to test these changes.
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
CC: Sascha Hauer <ker...@pengutronix.de>
CC: Martin Fuzzey <mfuz...@gmail.com>
---
[as1685]
drivers/usb/host/imx21-hcd.c | 43 ++++++++++++++++++++++++++-----------------
1 file changed, 26 insertions(+), 17 deletions(-)
Index: usb-3.9/drivers/usb/host/imx21-hcd.c
===================================================================
--- usb-3.9.orig/drivers/usb/host/imx21-hcd.c
+++ usb-3.9/drivers/usb/host/imx21-hcd.c
@@ -809,26 +809,36 @@ static int imx21_hc_urb_enqueue_isoc(str
/* calculate frame */
cur_frame = imx21_hc_get_frame(hcd);
- if (urb->transfer_flags & URB_ISO_ASAP) {
- if (list_empty(&ep_priv->td_list))
- urb->start_frame = cur_frame + 5;
- else
- urb->start_frame = list_entry(
- ep_priv->td_list.prev,
- struct td, list)->frame + urb->interval;
- }
- urb->start_frame = wrap_frame(urb->start_frame);
- if (frame_after(cur_frame, urb->start_frame)) {
- dev_dbg(imx21->dev,
- "enqueue: adjusting iso start %d (cur=%d) asap=%d\n",
- urb->start_frame, cur_frame,
- (urb->transfer_flags & URB_ISO_ASAP) != 0);
- urb->start_frame = wrap_frame(cur_frame + 1);
+ i = 0;
+ if (list_empty(&ep_priv->td_list)) {
+ urb->start_frame = wrap_frame(cur_frame + 5);
+ } else {
+ urb->start_frame = wrap_frame(list_entry(ep_priv->td_list.prev,
+ struct td, list)->frame + urb->interval);
+
+ if (frame_after(cur_frame, urb->start_frame)) {
+ dev_dbg(imx21->dev,
+ "enqueue: adjusting iso start %d (cur=%d)
asap=%d\n",
+ urb->start_frame, cur_frame,
+ (urb->transfer_flags & URB_ISO_ASAP) != 0);
+ i = DIV_ROUND_UP(wrap_frame(
+ cur_frame - urb->start_frame),
+ urb->interval);
+ if (urb->transfer_flags & URB_ISO_ASAP) {
+ urb->start_frame = wrap_frame(urb->start_frame
+ + i * urb->interval);
+ i = 0;
+ } else if (i >= urb->number_of_packets) {
+ ret = -EXDEV;
+ goto alloc_dmem_failed;
+ }
+ }
}
/* set up transfers */
+ urb_priv->isoc_remaining = urb->number_of_packets - i;
td = urb_priv->isoc_td;
- for (i = 0; i < urb->number_of_packets; i++, td++) {
+ for (; i < urb->number_of_packets; i++, td++) {
unsigned int offset = urb->iso_frame_desc[i].offset;
td->ep = ep;
td->urb = urb;
@@ -840,7 +850,6 @@ static int imx21_hc_urb_enqueue_isoc(str
list_add_tail(&td->list, &ep_priv->td_list);
}
- urb_priv->isoc_remaining = urb->number_of_packets;
dev_vdbg(imx21->dev, "setup %d packets for iso frame %d->%d\n",
urb->number_of_packets, urb->start_frame, td->frame);
--
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