use invd instead of wbinvd in real mode start code

[Bin Meng]

Hi Andy,

On Mon, Feb 17, 2020 at 9:47 PM Andy Shevchenko
<andy.shevchenko at gmail.com> wrote:
>
> (Cc'ing mailing list and Tom again, thus keep entire previous answer)
>
> On Mon, Feb 17, 2020 at 3:39 PM Andy Shevchenko
> <andy.shevchenko at gmail.com> wrote:
> > On Mon, Feb 17, 2020 at 2:41 PM Masahiro Yamada <masahiroy at kernel.org> wrote:
> > > On Mon, Feb 17, 2020 at 9:31 PM Andy Shevchenko
> > > <andy.shevchenko at gmail.com> wrote:
> >
> > > > It seems Masahiro's patches (don't know yet which one out of two,
> > > > probably invd one) broke the boot on Intel Edison.
> > > >
> > > > Reverting (both for now) helps.
> > >
> > > Why both?
> >
> > Because I did bisecting by intuition (much faster than usual one).
> >
> > > git bisect is the usual way to figure out the culprit.
> >
> > Too much work to do this way.
> >
> > And since I was about to have my lunch, I didn't continue
> > investigating. Let me do it now.
>
> OK, as my intuition told me the problematic one is
>
> commit 0d67fac29f3187e67f4fd3ef15f73e91be2fad12
> Author: Masahiro Yamada <masahiroy at kernel.org>
> Date:   Wed Jan 8 20:08:44 2020 +0900
>
>    x86: use invd instead of wbinvd in real mode start code
>
>
> Please, revert or fix ASAP before v2020.04 release!
> ^^^
>
> > > > P.S. I dunno how it has been tested, so, if you have Intel Edison in
> > > > possession, please, don't forget to test on it. It's not first time
> > > > the Intel Edison behaviour is broken due to poor testing.
> > >
> > >
> > > I tested my patches on qemu.
> >
> > Exactly my point of definition "poor".
> > It's not first time (and not last) when QEmu sucks.
> >
> > > Sorry for the breakage on your board, but I do not
> > > have Edison board.
> > > It is not possible to test every board.
> >
> > No problem, it's rather to x86 maintainers to have at least one-two
> > real hardware testing before applying this.
> > QEMU is completely not enough!
>

Is that because on Intel Edison U-Boot is not the first stage bootloader?

Regards,
Bin