Re: [PATCH 4.9 64/76] parisc: Detect QEMU earlier in boot process

[Greg Kroah-Hartman]

On Tue, Apr 16, 2019 at 03:50:16PM +0200, Helge Deller wrote:
> Hi Greg,
> 
> please do NOT apply this patch to the 4.9 tree.
> See below, it was tagged for v4.14+ only.

Yes, but I added it to 4.9 because:

> > commit d006e95b5561f708d0385e9677ffe2c46f2ae345 upstream.
> >
> > While adding LASI support to QEMU, I noticed that the QEMU detection in
> > the kernel happens much too late. For example, when a LASI chip is found
> > by the kernel, it registers the LASI LED driver as well.  But when we
> > run on QEMU it makes sense to avoid spending unnecessary CPU cycles, so
> > we need to access the running_on_QEMU flag earlier than before.
> >
> > This patch now makes the QEMU detection the fist task of the Linux
> > kernel by moving it to where the kernel enters the C-coding.
> >
> > Fixes: 310d82784fb4 ("parisc: qemu idle sleep support")

This commit is in 4.9.76.  So why wouldn't it be valid in 4.9.y (with
the exception of the fact that it doesn't build...)?

thanks,

greg k-h