On Fri, Jul 08, 2011 at 03:28:00PM +0200, Michal Hybner wrote:
> Hi all,
> I am connected to internet with IPWireless modem (it's using UMTS-TDD
> technology) using 1Mb/s tariff. But on Linux, its bandwidth never gets
> over 56 kB/s. I tried it on Windows and it works on full speed,
> sometimes even over 110 kB/s. I searched a lot about this issue
> because I am using Linux 99% of time. I found some posts aged approx.
> 5 years ago, that some people had this issue with 3G modems and it was
> due to low buffer size in 'usb-serial' driver which wasn't meant for
> those speed. As workaround was often recommended some dirty hack to
> increase buffer size by patching usb-serial or they advise to use
> 'option' driver. But 'option' didn't work for me - I used the 'echo
> 0bc3 0001 > /sys/.../new_id' thing and it didn't even connect. I think
> that 'option' driver is really for classic 3G FDD modems, but not TDD.
> I had opportunity to try it on 5 kernel versions - from 2.6.26 to
> 3.0.0-rc5 and it's always the same.
>
> Any advices how to solve this? If the bottleneck is really the buffer
> size, isn't it possible to set it somehow in the 'ipw' driver? Maybe
> it is simple to find, but I can't code :-(. Few days ago I found this
> patch[1] - maybe something similar could be done for 'ipw' driver too?
> 'lsusb -v' and 'lspci -v' attached.
Yes, a patch like that one should help out a lot here, are you able to
test patches?
If so, can you try the one below and let me know if it helps you out or
not?
thanks,
greg k-h
diff --git a/drivers/usb/serial/ipw.c b/drivers/usb/serial/ipw.c
index ca77e88..eaeb450 100644
--- a/drivers/usb/serial/ipw.c
+++ b/drivers/usb/serial/ipw.c
@@ -297,6 +297,8 @@ static struct usb_serial_driver ipw_device = {
.usb_driver = &usb_ipw_driver,
.id_table = usb_ipw_ids,
.num_ports = 1,
+ .bulk_in_size = 256,
+ .bulk_out_size = 256,
.open = ipw_open,
.close = ipw_close,
.dtr_rts = ipw_dtr_rts,
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