Re: [OE-core] [PATCH v5 2/4] qemuarm64.conf: allow overriding QB_OPT_APPEND

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

Hi,

On Tue, May 27, 2025 at 12:53:20PM +0100, Richard Purdie wrote:
> On Tue, 2025-05-27 at 12:07 +0300, Mikko Rapeli via lists.openembedded.org wrote:
> > It enables qemu USB support which causes a reset
> > loop currently with u-boot.
> > 
> > Signed-off-by: Mikko Rapeli <mikko.rapeli@linaro.org>
> > ---
> > �meta/conf/machine/qemuarm64.conf | 2 +-
> > �1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/meta/conf/machine/qemuarm64.conf b/meta/conf/machine/qemuarm64.conf
> > index d310445a34..f086729641 100644
> > --- a/meta/conf/machine/qemuarm64.conf
> > +++ b/meta/conf/machine/qemuarm64.conf
> > @@ -20,7 +20,7 @@ QB_SMP ?= "-smp 4"
> > �QB_CPU_KVM = "-cpu host -machine gic-version=3"
> > �# For graphics to work we need to define the VGA device as well as the necessary USB devices
> > �QB_GRAPHICS = "-device virtio-gpu-pci"
> > -QB_OPT_APPEND = "-device qemu-xhci -device usb-tablet -device usb-kbd"
> > +QB_OPT_APPEND ?= "-device qemu-xhci -device usb-tablet -device usb-kbd"
> > �# Virtio Networking support
> > �QB_TAP_OPT = "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no"
> > �QB_NETWORK_DEVICE = "-device virtio-net-pci,netdev=net0,mac=@MAC@"
> 
> I am very worried about merging patches specifically to disable usb
> (here and in the selftest) since that is something we expect to work to
> allow the graphics images to work properly.
>
> Is there an upstream discussion about why usb causes the hang and/or
> any estimate on when it might get fixed? I'm partly tempted to revert
> the uboot version instead of this.

Please allow downstream configurations to override this. They may not
care about USB emulation with qemu/runqemu. Several layers try to
build upon qemuarm64 oe-core machine but may need to tweak things
to get to a working test setup.

With Linux kernel AFAIK qemu USB works well, and qemu itself.
u-boot is a different beast but we have developers working
on improving the situation and I've notified them of this
easy to test scenario. u-boot side needs to sync the USB
stack with Linux kernel side changes and this is not a small
task. Sadly no upstream discussion link currently.

Not a perfect answer but better than nothing I hope.

Cheers,

-Mikko