Fibocom L850-GL / Intel XMM7360

Mon Jun 22 08:45:55 UTC 2020

On Mon, Jun 22, 2020 at 06:51:50AM +0000, Wassenberg, Dennis wrote:
> Hi all,
> 
> I tested the PCI approach.
> 
> Unfortunately I had no luck. The kernel PCI driver at https://github.com/xmm7360/xmm7360-pci can not initiale the modem
> correctly. The modem stays at status=0xfeedb007. This seems to mean that the modem is (still) booting. After 20 seconds
> probing fails. The kernel driver gives up waiting for the device to boot.
> 
> So, both options: usb switch and native pci driver will not work.
> 
> Are there any ideas how to continue?
> 

Hi Dennis,

some time ago Johannes Berg was working on a WWAN subsystem for the Linux
kernel (
https://lore.kernel.org/netdev/20200225100053.16385-1-johannes@sipsolutions.net/T/#t
) which also mentioned the 'upcoming Intel 4G modem driver ("iosm")'.

Perhaps it might help to ask him what the current status of this project is.

Regards,
Reinhard

> Thank you & best regards,
> 
> Dennis
> 
> 
> On Thu, 2020-06-18 at 16:24 +0200, Dennis Wassenberg wrote:
> > Hi Bjørn,
> > 
> > thank you for your estimation.
> > 
> > > Do you have any confirmation that it is actually possible to switch this
> > > firmware into USB mode?  Are there other firmwares available with
> > > (possible) USB support?
> > > 
> > 
> > I don't have a confirmation that the USB mode will really work, especially on the new models.
> > 
> > Last year (Lenovo Thinkpad Whiskey Lake series) there was the possibility to choose between the slow modem (Fibocom
> > L830-EB) and the faster option Fibocom L850-GL. This year the slow modem ist the fast modem of the last year and the
> > fast modem is CAT16 Fibocom L860-GL.
> > 
> > Regarding the Lenovo Thinkpad Whiskey Lake series models I found some threads where the USB mode switch worked:
> > 
> > https://forums.lenovo.com/t5/Other-Linux-Discussions/WWAN-Fibocom-L850-GL-and-Linux-support/m-p/4318903?page=1#4327397
> > https://gmt-24.net/archives/1461
> > 
> > Thats why I assumed that this might work at newer Thinkpads as well.
> > 
> > Especially https://gmt-24.net/archives/1461 shows that your assumption regarding the bootloader and application mode
> > seems to be correct.
> > 
> > This comes out directly after disabling the PCIe link and directly after that:
> > [  162.799214] usb 1-6: new high-speed USB device number 5 using xhci_hcd
> > [  162.940604] usb 1-6: New USB device found, idVendor=8087, idProduct=07f5, bcdDevice= 0.00
> > [  162.940612] usb 1-6: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> > [  169.651754] usb 1-6: USB disconnect, device number 5
> > 
> > Now bcdDevice changed to real device id.
> > 
> > [  175.462630] usb 1-6: new high-speed USB device number 6 using xhci_hcd
> > [  175.620153] usb 1-6: New USB device found, idVendor=2cb7, idProduct=0007, bcdDevice= 3.33
> > [  175.620162] usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> > [  175.620167] usb 1-6: Product: L850-GL
> > [  175.620172] usb 1-6: Manufacturer: Fibocom Wireless Inc.
> > [  175.620176] usb 1-6: SerialNumber: 004999010640000
> > 
> > 
> > > Anyway, FWIW, I'd explore the PCIe driver option first if I were you.
> > > That's the only mode tested by anyone, so it is more likely to work.
> > 
> > Ok, I will try that approach and let you know my results.
> > 
> > Thank you & best regards,
> > 
> > Dennis
> > 
> > 
> > On Thu, 2020-06-18 at 15:36 +0200, Bjørn Mork wrote:
> > > "Wassenberg, Dennis" <Dennis.Wassenberg at secunet.com> writes:
> > > 
> > > > After that dmesg shows this:
> > > > [ 930.843781] usb 1-7: new high-speed USB device number 16 using xhci_hcd
> > > > [ 930.996572] usb 1-7: New USB device found, idVendor=8087, idProduct=07f5, bcdDevice= 0.00
> > > > [ 930.996577] usb 1-7: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> > > > [ 937.683939] usb 1-7: USB disconnect, device number 16
> > > > 
> > > > So, in general I think there should be USB lines routed to the M.2 slot but I have no idea why the device leaves
> > > > the
> > > > bus. It is possible to run the script again and again but in the end it will always disconnect automatically.
> > > 
> > > I know nothing about these modems, but my guess is that this is a
> > > bootloader mode. Mostly based on the assumption that there will be one,
> > > and that the vendor-id will be something non-Intel in application mode.
> > > 
> > > You can probably confirm this by capturing the full device descriptor,
> > > e.g by creating a udev rule to dump it or simply by snooping on the bus.
> > > 
> > > If this assumption is correct, then the firmware was supposed to boot
> > > into an application mode and then reconnect to the USB bus with its real
> > > device ID and descriptors.  This could be failing due to a firmware
> > > crash, maybe caused by this unexpected state.  Or more likely:  The
> > > firmware on this modem is built without support for the USB mode.
> > > 
> > > Do you have any confirmation that it is actually possible to switch this
> > > firmware into USB mode?  Are there other firmwares available with
> > > (possible) USB support?
> > > 
> > > 
> > > Anyway, FWIW, I'd explore the PCIe driver option first if I were you.
> > > That's the only mode tested by anyone, so it is more likely to work.
> > > 
> > > 
> > > 
> > > Bjørn
> > 
> > 
> 
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