Re: Sierra Wireless EM9191 integration issues in mhi+wwan

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Tue, Nov 02, 2021 at 05:55:34PM +0100, Aleksander Morgado wrote:
> > > > > [    7.189547] mhi mhi0: Transitioning from PM state: Linkdown or
> > > > > Error Fatal Detect to: SYS ERROR Process
> > > >
> > > > Hmm, I think the use of sync_power_up might be causing the issue here as it
> > > > forces the MHI state to fatal error.
> > > >
> > > > Ignore the previous diff and try the below one:
> > > >
> > > > diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
> > > > index 59a4896a8030..b1e8c7de4e54 100644
> > > > --- a/drivers/bus/mhi/pci_generic.c
> > > > +++ b/drivers/bus/mhi/pci_generic.c
> > > > @@ -637,7 +637,7 @@ static void mhi_pci_recovery_work(struct work_struct *work)
> > > >         if (err)
> > > >                 goto err_try_reset;
> > > >
> > > > -       err = mhi_sync_power_up(mhi_cntrl);
> > > > +       err = mhi_async_power_up(mhi_cntrl);
> >
> > Doh! Sorry, I modified the wrong function. Here is the correct one:
> >
> > diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
> > index 59a4896a8030..1e3c74bfbe34 100644
> > --- a/drivers/bus/mhi/pci_generic.c
> > +++ b/drivers/bus/mhi/pci_generic.c
> > @@ -743,7 +743,7 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> >                 goto err_unregister;
> >         }
> >
> > -       err = mhi_sync_power_up(mhi_cntrl);
> > +       err = mhi_async_power_up(mhi_cntrl);
> >         if (err) {
> >                 dev_err(&pdev->dev, "failed to power up MHI controller\n");
> >                 goto err_unprepare;
> >
> > Let's see how it goes :)
> >
> 
> Oh, wow, what a difference a single extra byte in the correct place makes! :D
> 
> This looks waaaaay better; I've rebooted the board at least 10 times
> now and all of them worked nicely, at least just the process to probe
> the device and get the control and net ports exposed looks very
> reliable now. I'll test the setup with ModemManager in the next days
> and see how everything goes. Thank you very much!
> 

That's great to hear! Let me know how your testing goes with ModemManager. I'll
then submit a patch to fix the pci-generic driver.

Thanks,
Mani