Re: [PATCH] MM: Wavecom: Forbidden Sierra Wireless MC7750

[Aleksander Morgado <aleksander lanedo com>]

On 05/27/2013 03:35 PM, Bjørn Mork wrote:
> Aleksander Morgado <aleksander lanedo com> writes:
> > On 05/27/2013 04:07 AM, Heiher wrote:
> > > Hello,
> > >
> > > When I disable qmi-wwan kernel module, the default plugin for MC7750 is
> > > 'wavecom' in ModemManager. The Sierra Wireless MC7750 (0x114f:0x68a2) is
> > > not wavecom complatible device. Should be forbidden it?
> >
> > That's completely unexpected.
>
> Shouldn't be.  The qcserial and qmi_wwan drivers expected it :)

Unexpected by ModemManager I meant :)

> > Did the MC7750 really report itself with
> > the Wavecom USB vendor ID? It should have been Sierra Wireless' vendor
> > ID (0x1199) not the Wavecom one (0x114f). Truth is that Sierra Wireless
> > bought Wavecom, so I guess they can do whatever they want with the USB
> > IDs, but this is just unfortunate :)
>
> Yes, it is a bit unfortunate, but it seems they use different vendor IDs
> for the MC7700, MC7710 and MC7750 based on looking at the drivers Lenovo
> provide.  That's why we have this:
>
> bjorn nemi:/usr/local/src/git/linux$ git grep MC77 drivers/usb/serial/
> drivers/usb/serial/qcserial.c:  {USB_DEVICE(0x1199, 0x901b)},   /* Sierra Wireless MC7770 */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x0f3d, 0x68a2, 0)},       /* Sierra Wireless 
> MC7700 Device Management */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x0f3d, 0x68a2, 2)},       /* Sierra Wireless 
> MC7700 NMEA */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x0f3d, 0x68a2, 3)},       /* Sierra Wireless 
> MC7700 Modem */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x114f, 0x68a2, 0)},       /* Sierra Wireless 
> MC7750 Device Management */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x114f, 0x68a2, 2)},       /* Sierra Wireless 
> MC7750 NMEA */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x114f, 0x68a2, 3)},       /* Sierra Wireless 
> MC7750 Modem */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x1199, 0x68a2, 0)},       /* Sierra Wireless 
> MC7710 Device Management */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x1199, 0x68a2, 2)},       /* Sierra Wireless 
> MC7710 NMEA */
> drivers/usb/serial/qcserial.c:  {USB_DEVICE_INTERFACE_NUMBER(0x1199, 0x68a2, 3)},       /* Sierra Wireless 
> MC7710 Modem */
>
>
> I assume the reason is related to their magic PID changing.  By varying
> the VID they can provide unique device IDs while still allowing the same
> firmware to change between the same set of PIDs.
>
> A not-so-nice side effect of this is that the Lenovo BIOS whitelisting
> of MC7750 doesn't apply to MC7710 modules.  They need a separate
> whitelist entry.  This might be an intentional side effect for all I
> know...

Ok, so the Wavecom plugin really needs to skip modems with VID 0x114f if
they're handled by the qcserial driver... let me hack that.

Thanks for the note, Bjørn :)

-- 
Aleksander