Hey,

On Tue, Nov 02, 2021 at 11:39:12PM +0530, Manivannan Sadhasivam wrote:
> 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.
> 

Can you please test the attached patch? We had an internal discussion and came
to a conclusion that the device is not handling the SYS_ERR case during host
bootup. So we need to adjust the SYS_ERR logic handling in host to workaround
it.

Thanks,
Mani

> Thanks,
> Mani