Re: [PATCH] bus: mhi: pci_generic: increase timeout value for operations to 24000ms

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

On Wed, Sep 29, 2021 at 03:17:04PM +0200, Aleksander Morgado wrote:
> Hey Mani,
> 
> > >> diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
> > >> index 4dd1077354af..e08ed6e5031b 100644
> > >> --- a/drivers/bus/mhi/pci_generic.c
> > >> +++ b/drivers/bus/mhi/pci_generic.c
> > >> @@ -248,7 +248,7 @@ static struct mhi_event_config modem_qcom_v1_mhi_events[] = {
> > >>
> > >>   static const struct mhi_controller_config modem_qcom_v1_mhiv_config = {
> > >>      .max_channels = 128,
> > >> -    .timeout_ms = 8000,
> > >> +    .timeout_ms = 24000,
> > >
> > >
> > >This modem_qcom_v1_mhiv_config config applies to all generic SDX24, SDX55 and SDX65 modules.
> > >Other vendor-branded SDX55 based modules in this same file (Foxconn SDX55, MV31), have 20000ms as timeout.
> > >Other vendor-branded SDX24 based modules in this same file (Quectel EM12xx), have also 20000ms as timeout.
> > >Maybe it makes sense to have a common timeout for all?
> > >
> >
> > Eventhough the baseport coming from Qualcomm for the modem chipsets are same, it is possible that the vendors might have customized the firmware for their own usecase. That could be the cause of the delay for modem booting.
> >
> > So I don't think we should use the same timeout of 2400ms for all modems.
> >
> 
> Please note it's 24000ms what's being suggested here, not 2400ms.
> 

Doh, sorry I missed one zero ;)

> > >Thomas, is the 24000ms value taken from experimentation, or is it a safe enough value? Maybe 20000ms as in other modules would have been enough?
> > >
> >
> > It was derived from testing I believe.
> 
> Following your reasoning above, shouldn't this 24000ms timeout be
> applied only to the Sierra Wireless EM91xx devices (which may have
> custom firmware bits delaying the initialization a bit longer), and
> not to the generic SDX24, SDX55 and SDX65?
> 
> If I'm not mistaken, Thomas is testing with a custom mhi_pci_generic
> entry for the EM91xx; as in
> https://forum.sierrawireless.com/t/sierra-wireless-airprime-em919x-pcie-support/24927.
> I'm also playing with that same entry on my own setup, but have other
> problems of my own :)
> 

Hmm, then it makes sense to wait until we get the separate config from Thomas.

Thanks,
Mani

> 
> --
> Aleksander
> https://aleksander.es