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authorPete Zaitcev <zaitcev@redhat.com>2010-11-16 21:51:19 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-11-30 16:44:54 -0800
commitb17ea167c5fb50dcd5dce5b874a467f04eec886d (patch)
tree5a4714f6612e52e051d9b4495b3150466b3d3499 /drivers/usb
parent4f6838436915fdc281173bfd5bef6d8ab5cb1a7f (diff)
downloadop-kernel-dev-b17ea167c5fb50dcd5dce5b874a467f04eec886d.zip
op-kernel-dev-b17ea167c5fb50dcd5dce5b874a467f04eec886d.tar.gz
usbmon: correct length for isochronous
Usually the usbmon returns the amount of data specified in urb->transfer_buffer_length for output submissions and urb->actual_length for input callbacks. However, for Isochronous input transfers, this is not enough, since the returned data buffer may contain "holes". One easy way to fix this is to use urb->transfer_buffer_length, but this often transfers a whole lot of unused data, so we find how much was actually used instead. Original patch by Márton Németh. See also kernel bug 22182. Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Márton Németh <nm127@freemail.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/mon/mon_bin.c34
1 files changed, 31 insertions, 3 deletions
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index 44cb37b..a4cae2e 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -437,6 +437,28 @@ static unsigned int mon_bin_get_data(const struct mon_reader_bin *rp,
return length;
}
+/*
+ * This is the look-ahead pass in case of 'C Zi', when actual_length cannot
+ * be used to determine the length of the whole contiguous buffer.
+ */
+static unsigned int mon_bin_collate_isodesc(const struct mon_reader_bin *rp,
+ struct urb *urb, unsigned int ndesc)
+{
+ struct usb_iso_packet_descriptor *fp;
+ unsigned int length;
+
+ length = 0;
+ fp = urb->iso_frame_desc;
+ while (ndesc-- != 0) {
+ if (fp->actual_length != 0) {
+ if (fp->offset + fp->actual_length > length)
+ length = fp->offset + fp->actual_length;
+ }
+ fp++;
+ }
+ return length;
+}
+
static void mon_bin_get_isodesc(const struct mon_reader_bin *rp,
unsigned int offset, struct urb *urb, char ev_type, unsigned int ndesc)
{
@@ -479,6 +501,10 @@ static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
/*
* Find the maximum allowable length, then allocate space.
*/
+ urb_length = (ev_type == 'S') ?
+ urb->transfer_buffer_length : urb->actual_length;
+ length = urb_length;
+
if (usb_endpoint_xfer_isoc(epd)) {
if (urb->number_of_packets < 0) {
ndesc = 0;
@@ -487,14 +513,16 @@ static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
} else {
ndesc = urb->number_of_packets;
}
+ if (ev_type == 'C' && usb_urb_dir_in(urb))
+ length = mon_bin_collate_isodesc(rp, urb, ndesc);
} else {
ndesc = 0;
}
lendesc = ndesc*sizeof(struct mon_bin_isodesc);
- urb_length = (ev_type == 'S') ?
- urb->transfer_buffer_length : urb->actual_length;
- length = urb_length;
+ /* not an issue unless there's a subtle bug in a HCD somewhere */
+ if (length >= urb->transfer_buffer_length)
+ length = urb->transfer_buffer_length;
if (length >= rp->b_size/5)
length = rp->b_size/5;
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