Re: Kernel 6.5 ttyS1 hang with qemu (was Re: [OE-core] Summary of the remaining 6.5 kernel serial issue (and 6.5 summary)

[Mikko Rapeli <mikko.rapeli@linaro.org>]

Hi,

On Mon, Oct 16, 2023 at 10:23:52AM +0300, Tony Lindgren wrote:
> * Mikko Rapeli <mikko.rapeli@linaro.org> [231016 07:16]:
> > On Mon, Oct 16, 2023 at 09:35:01AM +0300, Tony Lindgren wrote:
> > > * Richard Purdie <richard.purdie@linuxfoundation.org> [231015 21:30]:
> > > > On Sun, 2023-10-15 at 17:31 +0200, Greg Kroah-Hartman wrote:
> > > > > Can you try the patch below?  I just sent it to Linus and it's from Tony
> > > > > to resolve some other pm issues with the serial port code.
> > > > 
> > > > Thanks for the pointer to this. I've put it through some testing and
> > > > had one failure so far so I suspect this isn't enough unfortunately.
> > > >
> > > > FWIW I was looping the testing on the complete removal of the
> > > > conditions and didn't see any failures with that.
> > > 
> > > Care to clarify what's the failing test now?
> > > 
> > > Is the issue still the second port not always coming up after boot or
> > > something else?
> > 
> > Yes, data from the ttyS1 getty is not coming through from kernel and qemu to
> > the test framework looking for login prompt after qemu machine boot.
> > Workarounds like sending "\n\n" from the test framework through qemu to ttyS1
> > or "echo helloB > /dev/ttyS1" via working ttyS0 don't seem to help and wake
> > it up.
> 
> OK so for trying to reproduce this with qemu, is this with the default uarts
> or with some -device pci-serial-2x type options?

Here is how yocto test frameworks starts qemu:

qemu-system-x86_64 -device virtio-net-pci,netdev=net0,mac=52:54:00:12:35:07 -netdev user,id=net0,hostfwd=tcp:127.0.0.1:2225-:22,hostfwd=tcp:127.0.0.1:2325-:23,tftp=/home/builder/src/base/build_test/tmp/deploy/images/qemux86-64 -object rng-random,filename=/dev/urandom,id=rng0 -device virtio-rng-pci,rng=rng0 -drive file=/home/builder/src/base/build_test/tmp/deploy/images/qemux86-64/core-image-ptest-openssh-qemux86-64.rootfs.ext4,if=virtio,format=raw -usb -device usb-tablet -usb -device usb-kbd   -cpu IvyBridge -machine q35,i8042=off -smp 4 -enable-kvm -m 1024 -serial tcp:127.0.0.1:46313 -serial tcp:127.0.0.1:53891  -pidfile /home/builder/src/base/build_test/pidfile_1926373  -S -qmp unix:./.lzkynxe1,server,wait -qmp unix:./.qcpdyz4j,server,nowait -snapshot -nographic  -kernel /home/builder/src/base/build_test/tmp/deploy/images/qemux86-64/bzImage -append 'root=/dev/vda rw  ip=dhcp console=ttyS0 console=ttyS1 oprofile.timer=1 tsc=reliable no_timer_check rcupdate.rcu_expedited=1 swiotlb=1  printk.time=1'

Example boot log when this ttyS1 failure happens is here:

https://pastebin.com/raw/jRRa2CwW

Cheers,

-Mikko