Re: mhi resume failure on reboot with 6.13-rc2

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

Adding Loic, since he authored the pci_generic driver and knows more about
modems than me.

- Mani

On Mon, Dec 16, 2024 at 01:10:34PM +0530, Manivannan Sadhasivam wrote:
> On Wed, Dec 11, 2024 at 04:03:59PM +0100, Johan Hovold wrote:
> > On Wed, Dec 11, 2024 at 08:23:15PM +0530, Manivannan Sadhasivam wrote:
> > > On Wed, Dec 11, 2024 at 03:17:22PM +0100, Johan Hovold wrote:
> > 
> > > > I just hit the following modem related error on reboot of the x1e80100
> > > > CRD for the second time with 6.13-rc2:
> > > > 
> > > > 	[  138.348724] shutdown[1]: Rebooting.
> > > >         [  138.545683] arm-smmu 3da0000.iommu: disabling translation
> > > >         [  138.582505] mhi mhi0: Resuming from non M3 state (SYS ERROR)
> > > >         [  138.588516] mhi-pci-generic 0005:01:00.0: failed to resume device: -22
> > > >         [  138.595375] mhi-pci-generic 0005:01:00.0: device recovery started
> > > >         [  138.603841] wwan wwan0: port wwan0qcdm0 disconnected
> > > >         [  138.609508] wwan wwan0: port wwan0mbim0 disconnected
> > > >         [  138.615137] wwan wwan0: port wwan0qmi0 disconnected
> > > >         [  138.702604] mhi mhi0: Requested to power ON
> > > >         [  139.027494] mhi mhi0: Power on setup success
> > > >         [  139.027640] mhi mhi0: Wait for device to enter SBL or Mission mode
> > > > 
> > > > and then the machine hangs.
> > > > 
> > > > Do you know if there are any changes since 6.12 that could cause this?
> > > 
> > > Only 3 changes went in for 6.13-rc1 and they shouldn't cause any issues. One
> > > caused the regression with pcim_iomap_region(), but you submitted a fix for
> > > that and other two were trivial.
> > 
> > Ok, thanks.
> > 
> > > From the log, 'mhi mhi0: Resuming from non M3 state (SYS ERROR)' indicates that
> > > the firmware got crashed while resuming. So maybe you should check with ath12k
> > > folks.
> > 
> > This is the modem so I don't think the ath12k wifi folks are to blame
> > here.
> > 
> 
> Ah, even after these years I always confuse between WLAN and WWAN :)
> 
> > It may be an older, existing issue that started triggering due to
> > changes in timing or something.
> >
> 
> Could be. But the issue seems to be stemming from the modem crash while exiting
> M3. You can try removing the modem autosuspend by skipping the if condition
> block:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/bus/mhi/host/pci_generic.c?h=v6.13-rc1#n1184
> 
> If you no longer see the crash, then the issue might be with modem not coping
> up with autosuspend. If you still see the crash, then something else going wrong
> during reboot/power off.
> 
> > Is there anything you can do on the mhi side to prevent it from blocking
> > reboot/power off?
> > 
> 
> It should not block the reboot/power off forever. There is a timeout waiting for
> SBL/Mission mode and the max time is 24s (depending on the modem). Can you share
> the modem VID:PID?
> 
> - Mani
> 
> -- 
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