Hello.
On 17-11-2010 7:51, Pete Zaitcev wrote:
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 MÃrton NÃmeth. See also kernel bug 22182.
Signed-off-by: Pete Zaitcev<zaitcev@xxxxxxxxxx>
[...]
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index 44cb37b..946e3b1 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;
+ }
{} are not needed here, and thwo *if* statements can be collapsed into one.
+ fp++;
Could be a *for* loop instead...
+ }
+ 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)
{
WBR, Sergei
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