[PATCH 2/2] ACPI / video / i915: Remove ACPI backlight if firmware expects Windows 8
corsac at debian.org
Wed Sep 11 02:09:25 PDT 2013
On mer., 2013-09-11 at 08:45 +0000, Matthew Garrett wrote:
> On Wed, 2013-09-11 at 11:45 +0300, Jani Nikula wrote:
> > Before plunging forward, have you observed any difference between the
> > boot modes? We have reports  that the backlight behaviour is
> > different with UEFI vs. UEFI+CSM or legacy boot. So I'm wondering if the
> > acpi_gbl_osi_data >= ACPI_OSI_WIN_8 check in patch 2/2 is the whole
> > story.
> > Further, if we tell the BIOS we're Windows 8 to use the tested BIOS code
> > paths, what guarantees do we have of UEFI+CSM or legacy boots working?
> We have no evidence of Windows behaving differently based on the exposed
> firmware type.
I do have an X230 which boots fine using pure UEFI or UEFI+CSM (and I
guess I can try booting it with a grml for pure legacy), so I can do
tests if needed.
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