Re: USB Serial Converter driver and multiple devices

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 2012-05-14 at 08:24 -0700, Greg KH wrote:
> On Mon, May 14, 2012 at 06:14:14PM +0300, Olli Helin wrote:
> > > > I recently got myself a 3G USB modem, which uses the usbserial driver.
> > > > I have to give the usbserial module the vendor and product IDs as
> > > > command line arguments for the driver to work with my modem.  
> > > 
> > > Stop right there.  Why do you need to do this?  You shouldn't, it should
> > > "just work" without this.  What type of device is this, and what driver
> > > are you adding the device id to (hint, it can't be the generic
> > > usb-serial one, that is not for a "real" device, but only for testing.)  
> > 
> > It indeed is the generic usb-serial one.
> 
> Ick, that makes use of it very slow, as the generic usb-serial driver is
> designed to be slow and not for real devices at all.
> 
> > The device in question is
> > Telewell TW-3G HSPA+, and I'm loading usbserial with vendor=0x1c9e
> > product=0x9801 to get it to work. It is a "traditional" 3G modem which
> > is seen as a CD rom device first, and as a modem after modeswitch.
> > However, it doesn't have usb_modeswitch rules readily available
> > (that's why it does not "just work"), so I made one for myself. I know
> > I should submit it to usb_modeswitch devs, however I haven't yet as
> > using the usbserial driver for it seemed quite weird, and I started
> > testing with a custom Gobi Serial driver first. With it everything
> > seems to work fine. When using the usbserial driver, with my Ubuntu
> > 10.04 and its older kernel (2.6.x) the system was frozen until I
> > disconnected the modem. Using Gentoo with 3.x kernel, both usbserial
> > and Gobi Serial work. The manufacturer says that it is a known problem
> > "with older kernels and their usbserial module"; about more specific
> > version numbers I have no clue.
> 
> That's really wierd, and I do not know of any such "known problems" at
> all.  It would be nice if the vendors actually talked to the people
> supporting and writing their drivers, now wouldn't it :(
> 
> > > > My 3G modem actually worked with the Gobi Serial (CodeAurora) driver
> > > > after setting the device ID in the MODULE_DEVICE_TABLE, so I wouldn't
> > > > have a problem right now even if I had another device using the
> > > > usbserial driver directly. I also understand this would be a rare
> > > > situation and hardly a practical problem, but I'm just asking.  
> > > 
> > > Care to send a patch that adds your device id to this driver so it will
> > > work for everyone?  
> > 
> > I downloaded the Gobi Serial driver "template" from CodeAurora home
> > page, added the product info USB_DEVICE( 0x1c9e, 0x9801 ), and added
> > an include clause for compiling on Linux 3.x. So far no problems. What
> > would be the correct module to patch in the Linux kernel then? I guess
> > USB Qualcomm Serial modem, no?
> 
> No, try the option driver.  You can add the device id to the new_id
> sysfs file for the driver and see if that works out properly.  If so,
> create a patch following the information in the
> Documentation/SubmittingPatches file and send it to us so I can apply
> it.

No, not option.  If it's a Gobi-derived device, then it needs IDs in
qcserial, qmi_wwan, and possibly fixups for cdc-wdm.  Gobi devices
should *never* be handled by option.

Dan

> > > And as for a solution, again, the generic usb-serial driver is not for a
> > > real device, that is why it can accept only one device id through the
> > > module parameters.  
> > 
> > I guess the hardware manufacturers have abused the ability to give
> > modules parameters then, huh?
> 
> It looks like they have.
> 
> > They specifically instruct one to use the usbserial driver with the
> > module parameters for their device. The information about using the
> > Gobi Serial driver I only got after asking them what's the deal with
> > using the generic usbserial driver.
> 
> Where online is this information?  And yes, it sounds completely
> incorrect and wrong.
> 
> thanks,
> 
> greg k-h
> --
> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux