use invd instead of wbinvd in real mode start code

Andy Shevchenko
2020-02-17T13:47:18Z

(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@gmail.com> wrote:
> On Mon, Feb 17, 2020 at 2:41 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
> > On Mon, Feb 17, 2020 at 9:31 PM Andy Shevchenko
> > <andy.shevchenko@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@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!

--
With Best Regards,
Andy Shevchenko