The Power9 host booting problem with OpenBMC kernel 5.7.x

[Joel Stanley]

Thanks for the response. I've merged the two threads, and I have a
candidate for a fix.

On Tue, 11 Aug 2020 at 18:33, Alexander A. Filippov
<a.filippov at yadro.com> wrote:
> With the kerenl 5.8 the host is still not booting.
> I've checked on both machines and they have very different results:
>  - On the machine with two CPUs the issue is still reproduced.
>    I see no difference, neither in the behavior, nor in the logs.
>  - On the machine with one CPU the failure happens due the PNOR flash.
>    It looks like this:

>
> I've noticed that the kernel 5.8 detect the flash driver incorrectly:
> mx25l51245g instead of mx66l51235f.
> It happens on both machines and I don't understand why it leads to the problems
> on only one of them.

I found upstream v5.8 has a regression in the spi-nor driver on
aspeed. I've put a revert of the patch that caused the regression on
the list, but it requires some more investigation to find a proper
fix:

 https://patchwork.ozlabs.org/project/openbmc/patch/20200812035847.2352277-1-joel@jms.id.au/

On Tue, 11 Aug 2020 at 11:54, Artem Senichev <artemsen at gmail.com> wrote:
> > My guess is it's something to do with the timekeeping, irq or rcu
> > code. All areas of complexity!
> >
>
> We had similar behaviour in P8 when tried to use ColdFire FSI:
> https://github.com/openbmc/openbmc/issues/3433
>
> In this issue, htop shows 100% load of one CPU on the host and it is not an OS
> task. Looks like FSI doesn't stop working and fully loads one core.

I think we have an issue with the irq polarity of the vuart device.
Did you notice an excessive number of lpc_serirq interrupts on the
host (check /proc/interrupts)?

Try doing this on your BMC before booting your host:

root at bmc:~# echo 0 >
/sys/devices/platform/ahb/ahb:apb/1e787000.serial/sirq_polarity

If that fixes it we can make a change to the device tree to make the
setting permanent.

Cheers,

Joel