[PATCH] x86: Introdudce a new option --force-vga

Dave Young dyoung at redhat.com
Tue Mar 5 02:09:07 PST 2019


On 03/05/19 at 04:24pm, Kairui Song wrote:
> On Mon, Mar 4, 2019 at 2:30 PM Dave Young <dyoung at redhat.com> wrote:
> >
> > On 02/28/19 at 06:07pm, Kairui Song wrote:
> > > After commit 060eee58 "x86: use old screen_info if needed", kexec-tools
> > > will force use old screen_info and vga type if failed to determine
> > > current vga type. But it is not always a good idea.
> > >
> > > Currently kernel hanging is inspected on some hyper-v VMs after this
> > > commit, because hyperv_fb will mimic EFI (or VESA) VGA on first boot
> > > up, but after the real driver is loaded, it will switch to new mode
> > > and no longer compatible with EFI/VESA VGA. Keep setting
> > > orig_video_isVGA to EFI/VESA VGA flag will get wrong driver loaded and
> > > try to manipulate the framebuffer in a wrong way.
> > >
> > > We can't ensure this won't happen on other framebuffer drivers, But
> > > it's a helpful feature if the framebuffer drivers just work. So this
> > > patch introduce a --force-vga options to let user decide if the
> > > old screen_info should be used unconditional or not.
> >
> > It looks good to me except the option name, because vga usually means
> > the specific vga video type.  But here you are enforcing to reuse the first
> > kernel original video type.
> >
> > It would be better to use --reuse-video-type or --force-orig-video, etc..
> >
> 
> Thanks for the review, the naming is not very good indeed, will update
> the patch. How about just --reuse-video? This should be general enough
> and clear.

Hmm, I feel --reuse-video-type is clearer,  --reuse-video seems not
clear :)

> 
> -- 
> Best Regards,
> Kairui Song



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