[linux-elitists] USB-Serial and pppd

Matthew Galgoci mgalgoci@redhat.com
Thu Jun 12 10:59:52 PDT 2008

> Yes, the option driver can (and should) be changed to go faster.  It's a
> simple one line change.
> In drivers/usb/serial/option.c, change the line:
> 	#define N_OUT_URB 1
> to be:
> 	#define N_OUT_URB 4
> Your upload throughput should increase a bit.
> Another number to look at is the output buffer size, if you are doing
> lots of uploads.  Change:
> 	#define OUT_BUFLEN 128
> to
> 	#define OUT_BUFLEN 4096
> The combination of the two changes should help out a lot.
> The dowload speed should be pretty much as fast as the network allows,
> but that all depends on your local connection.  If you want to test it
> out, you can change the line in the driver:
> 	#define N_IN_URB 4
> to be a larger number, like 8:
> 	#define N_IN_URB 8
> It probably will not matter that much, but it might.

Thanks man! I'll do some testing as I'll be traveling this weekend and
tethered to my card.

Matthew Galgoci
Network Operations
Red Hat, Inc
919.754.3700 x44155

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