Virtio_console usage of early printk

[Alexander Graf]

On 22.03.2010, at 18:45, François Diakhate wrote:

> Hi all,
> 
> As far as I can see, early_put_chars is not used by virtio_console
> because it checks whether there is a port available before using it.
> If I understand correctly, this makes it useless because once we have
> a port, we can use the regular virtio transport to output things to
> the console. Does the attached patch seem valid ? Feedback from s390
> and powerpc users who use this functionality would be appreciated.

On S390 we use the hypercall interface with characters instead of memory addresses as parameters. The hypervisor then decides if the character is an early printk or a real hypercall.

I'm not sure how PPC handles that - I never used virtio console there.

Either way, early printk does work for S390. So what exactly is this patch supposed to fix?


Alex