Re: [Bug 215433] New: data connection lost on Qualcomm SDX55 PCIe device

[Bjorn Helgaas <helgaas@kernel.org>]

[+cc MHI folks]

On Tue, Dec 28, 2021 at 11:26:02AM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=215433
> 
>            Summary: data connection lost on Qualcomm SDX55 PCIe device
>     Kernel Version: 5.13.0,5.15.0
> ...

> For Qualcomm based modem devices, with PCIE interface, and mhi driver based on
> kernel 5.13.0, it will lose data connection. Details as below:
> 
>     Phenomenon:
>         1) Can NOT connect to Internet
>         2) /dev/wwan0p1QCDM, /dev/wwan0p2MBIM, /dev/wwan0p3AT NOT response
> 
>     Reproduce steps
>         1) Connect Internet via cellular
>         2) Do speedtest(https://www.speedtest.net/) or download a 1GB file
> (ipv4.download.thinkbroadband.com/1GB.zip)
> 
>     Recovery method
>         Only can be recovered by reboot host
> 
>     Others
>         It can NOT be reproduced in Windows 10/11.

Thanks very much for the report.  I'm not familiar with the mhi
driver, so I added some folks who might be.

Can you please collect the complete dmesg log and output of
"sudo lspci -vv" and attach both to the bugzilla?

Does the network connection work for a while, then stop working?  If
so, is there anything logged in the dmesg log when it stops working?

Do you know of any Linux versions that do not have this problem?  If
it used to work but it got broken, that would help narrow things down.

Thanks,
  Bjorn