Re: GNSS support for Qualcomm PCIe modem device

[Muhammad Nuzaihan]

Hi Sergey, Slark,

Using wwan subsystem and it works without issues, maybe i might miss
something, perhaps the flow control but i never have any problems even
without flow control.

I am using gpsd + cgps and xgps with a small modification to Linux
kernel's wwan subsystem in the kernel to get NMEA data.

I had posted the patch previously and i can post the patch again if you like.

Attached in this email is the screenshot of cgps + gpsd.

Maybe it should be in GPS subsystem but it's working for me even using
wwan subsystem for months now.

Regards,
Zaihan
On Fri, Apr 4, 2025 at 5:46 AM Sergey Ryazanov <ryazanov.s.a@xxxxxxxxx> wrote:
>
> Hi Slark, Zaihan,
>
> Zaihn, congratulations with the progress, curious to see the result.
>
> Slark, thank you for remind me. It's a good moment. Lets see how we can
> prototype it. Will try to do it this weekend and send some RFC next week.
>
> On 03.04.2025 11:42, Muhammad Nuzaihan wrote:
> > Hi Slark,
> >
> > I just implemented it in the wwan subsystem since it works for me (even
> > without flow control). I wanted to port it to use GPS subsystem,
> > however, debugging in GPS subsystem is too troublesome, especially when
> > the driver crashes.
> >
> > Unless i can have some VM with direct access to the Quectel hardware so
> > i don't need to keep rebooting my machine if it crashes.
> >
> > For now, i am getting GNSS/NMEA data from Quectel with MHI wwan
> > modifications.
> >
> > Regards,
> > Zaihan
> >
> >
> > On Thu, Apr 3 2025 at 04:02:01 PM +0800, Muhammad Nuzaihan
> > <zaihan@xxxxxxxxxxxxxx> wrote:
> >> Hi Slark,
> >>
> >> I just implemented it in the wwan subsystem since it works for me
> >> (even without flow control). I wanted to port it to use GPS subsystem,
> >> however, debugging in GPS subsystem is too troublesome, especially
> >> when the driver crashes.
> >>
> >> Unless i can have some VM with direct access to the Quectel hardware
> >> so i don't need to keep rebooting my machine if it crashes.
> >>
> >> For now, i am getting GNSS/NMEA data from Quectel with MHI wwan
> >> modifications.
> >>
> >> Regards,
> >> Zaihan
> >>
> >> On Thu, Apr 3 2025 at 02:06:52 PM +0800, Slark Xiao
> >> <slark_xiao@xxxxxxx> wrote:
> >>>
> >>> Hi Sergey, Muhammad,
> >>> This is Slark. We have a discussion about the feature of GNSS/NMEA
> >>> over QC PCIe modem
> >>> device since 2024/12.May I know if we have any progress on this feature?
> >>>
> >>> It's really a common requirement for modem device since we have
> >>> received some complaint
> >>> from our customer. Please help provide your advice.
>
> --
> Sergey

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