Re: [RFT] x86 acpi: normalize segment descriptor register on resume

Pavel Machek
2008-07-13T08:55:29Z

Hi!

> > > Is there an Intel graphics in your box?
> >
> > Yes.
> >
> > >
> > >> -rc8 and -rc9 with the original patch 4b4f7280 resume fine no matter how
> > >> I suspend.
> > >
> > > That's _really_ strange.
> > >
> > > In fact I have only one explanation, which is that the Gnome suspend button
> > > causes some user-space quirks to be applied, which are harmful and break the
> > > resume. Also, without commit 4b4f7280 those quirks might have not been really
> > > executed. Peter, does it sound reasonable?
> >
> > Bingo. It's a HAL quirk.
> >
> > Testing from the console (not X):
> >
> > With 4b4f7280:
> > # echo mem >/sys/power/state -- works fine
> >
> > # echo 3 >/proc/sys/kernel/acpi_video_flags
> > # echo mem >/sys/power state -- fails to resume
> >
> > Without 4b4f7280:
> > # echo mem >/sys/power/state -- works fine
> >
> > # echo 3 >/proc/sys/kernel/acpi_video_flags
> > # echo mem >/sys/power state -- works fine
> >
> > So HAL contains an apparently unnecessary quirk for my laptop, and
> > 4b4f7280 breaks that quirk. Of course, it's entirely possible that
> > 4b4f7280 is 100% correct, but that the quirk only worked by accident and
> > 4b4f7280 broke the call into video BIOS.
>
> We've had reports from users of Intel graphics and the i915 driver that
> previously working quirks started to break their systems with 2.6.26-rc, but
> instead the plain "echo mem > /sys/power/state" started to work for them.
> Your system may be one of these, but I wonder what the effect of commit
> 4b4f7280 is.

In such case, you could verify by disabling intel framebuffer and just
using plain VGA driver (or vesafb).

Breaking video bios calls would be bad.
Pavel

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