usbserial speed limitations ?

usbserial speed limitations ?

[Paul Rolland]

Hello,

I'm about to start working with a new USB 3G+ modem (Novatel Wireless
M996D), details :

  Product ID:	0x5023
  Vendor ID:	0x1410  (Novatel Wireless, Inc.)
  Version:	 0.00
  Speed:	Up to 480 Mb/sec
  Manufacturer:	Novatel Wireless, Inc

>From the manufacturer web site, regarding the installation, I can read :

"Maximum connection speed is limited by the current generic usbserial
driver to approximately less than 500kbps."

Is there really such a speed limitation in the usbserial module/driver ?
This modem is HSPA+, which should allow a theorical maximum downspeed of
20MBps, not 500kbps...

The machine intended for such use in 2.6.28.x. Is there any chance to have
something better with a newer kernel ?

Any help / hint appreciated...

Regards,
Paul

Re: usbserial speed limitations ?

[Oliver Neukum]

Am Donnerstag, 4. Februar 2010 09:58:55 schrieb Paul Rolland:
> "Maximum connection speed is limited by the current generic usbserial
> driver to approximately less than 500kbps."
> 
> Is there really such a speed limitation in the usbserial module/driver ?
> This modem is HSPA+, which should allow a theorical maximum downspeed of
> 20MBps, not 500kbps...

In the generic usbserial driver this speed limit indeed exists.
But you are not supposed to use it with that kind of device.
Most likely the correct driver would be either option or sierra.
Please post lsusb -v for your device.

	Regards
		Oliver

Re: usbserial speed limitations ?

[Paul Rolland]

Hi Oliver,

On Thu, 4 Feb 2010 12:26:21 +0100
Oliver Neukum <oliver@neukum.org> wrote:

> Am Donnerstag, 4. Februar 2010 09:58:55 schrieb Paul Rolland:
> > "Maximum connection speed is limited by the current generic usbserial
> > driver to approximately less than 500kbps."
> > 
> > Is there really such a speed limitation in the usbserial module/driver ?
> > This modem is HSPA+, which should allow a theorical maximum downspeed of
> > 20MBps, not 500kbps...
> 
> In the generic usbserial driver this speed limit indeed exists.
> But you are not supposed to use it with that kind of device.
> Most likely the correct driver would be either option or sierra.
> Please post lsusb -v for your device.

I don't have yet the device, but the informations I have so far are :
 - It is Vendor ID 0x1410, product ID 0x5023 when connected for the first
   time, and then it is a disk device.
 - Ejecting it makes it appear as Vendor ID 0x1410, product ID 0x7030

Novatel also refers to their procedure for the linux installation :
(http://www.nvtl.com/index.php?option=com_content&view=article&id=139&Itemid=305
which has a link to 
http://www.nvtl.com/index.php?option=com_content&view=article&id=176&Itemid=331)

This applies to Ovation MC930D and Ovation MC950D, which are supported by
option.c

So, I suspect the best would be to add the 0x7030 Product ID in the option
driver, and git it a shoot...

Regards,
Paul

Re: usbserial speed limitations ?

[Oliver Neukum]

Am Donnerstag, 4. Februar 2010 12:45:44 schrieb Paul Rolland:
> So, I suspect the best would be to add the 0x7030 Product ID in the option
> driver, and git it a shoot...

Yes, that's the best plan.

	Regards
		Oliver