[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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