staging: line6: use smallest iso ep packet size

The POD HD300 isochronous endpoints have different max packet sizes for
read and write.  Using the read endpoint max packet size may be too
large for the write endpoint.  Instead we should use the minimum of both
endpoints to be sure the size is acceptable.

In theory we could decouple read and write packet sizes but the driver
currently uses a single size which I chose not to mess with since other
features like software monitoring may depend on a single packet size for
both endpoints.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/line6/pcm.c b/drivers/staging/line6/pcm.c
index f56c6427c36ebb1dd8178125361cbf7597a3d2bf..ae984344749f034da61e83223e647fb394838716 100644 (file)
--- a/drivers/staging/line6/pcm.c
+++ b/drivers/staging/line6/pcm.c
@@ -452,9 +452,14 @@ int line6_init_pcm(struct usb_line6 *line6,
        line6pcm->line6 = line6;
        line6pcm->ep_audio_read = ep_read;
        line6pcm->ep_audio_write = ep_write;
-       line6pcm->max_packet_size = usb_maxpacket(line6->usbdev,
-                                                 usb_rcvintpipe(line6->usbdev,
-                                                                ep_read), 0);
+
+       /* Read and write buffers are sized identically, so choose minimum */
+       line6pcm->max_packet_size = min(
+                       usb_maxpacket(line6->usbdev,
+                               usb_rcvisocpipe(line6->usbdev, ep_read), 0),
+                       usb_maxpacket(line6->usbdev,
+                               usb_sndisocpipe(line6->usbdev, ep_write), 1));
+
        line6pcm->properties = properties;
        line6->line6pcm = line6pcm;