USB: limit usbfs snooping of URB contents
The usbfs_snoop facility can be very useful for debugging problems
involving usbfs. However, it always prints out the entire contents of
every URB. When dealing with large quantities of data, this can be
less than helpful.
This patch ameliorates the situation by adding a module parameter to
usbcore for controlling the maximum number of bytes to print when
snooping an URB. This makes debugging much easier. For backward
compatibility, the default value is set unreasonably high.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 742f69d..e6b6e056 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3874,6 +3874,10 @@
usbcore.usbfs_snoop=
[USB] Set to log all usbfs traffic (default 0 = off).
+ usbcore.usbfs_snoop_max=
+ [USB] Maximum number of bytes to snoop in each URB
+ (default = 65536).
+
usbcore.blinkenlights=
[USB] Set to cycle leds on hubs (default 0 = off).