This is a note to let you know that I've just added the patch titled
Subject: USB: increase usbdevfs max isoc buffer size
to my gregkh-2.6 tree. Its filename is
usb-increase-usbdevfs-max-isoc-buffer-size.patch
This tree can be found at
http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/
>From mrechberger@xxxxxxxxx Mon Aug 10 11:37:54 2009
From: Markus Rechberger <mrechberger@xxxxxxxxx>
Date: Sun, 9 Aug 2009 21:23:34 +0200
Subject: USB: increase usbdevfs max isoc buffer size
To: Steve Calfee <stevecalfee@xxxxxxxxx>
Cc: Oliver Neukum <oliver@xxxxxxxxxx>, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>, USB list <linux-usb@xxxxxxxxxxxxxxx>, npaknejad@xxxxxxxxx
Message-ID: <d9def9db0908091223o1a7671d4k42283a0648f967b0@xxxxxxxxxxxxxx>
The current limit only allows isochronous transfers up to 32kbyte/urb,
updating this to 192 kbyte/urb improves the reliability of the
transfer. USB 2.0 transfer is possible with 32kbyte but increases the
chance of corrupted/incomplete data when the system is performing some
other tasks in the background.
http://www.spinics.net/lists/linux-usb/msg19955.html
Signed-off-by: Markus Rechberger <mrechberger@xxxxxxxxx>
Cc: Oliver Neukum <oliver@xxxxxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/usb/core/devio.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1091,7 +1091,8 @@ static int proc_do_submiturb(struct dev_
}
totlen += isopkt[u].length;
}
- if (totlen > 32768) {
+ /* 3072 * 64 microframes */
+ if (totlen > 196608) {
kfree(isopkt);
return -EINVAL;
}
--
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