On Wed, 2013-09-11 at 13:29 +0300, Jani Nikula wrote: > On Wed, 11 Sep 2013, Matthew Garrett <matthew.garrett@xxxxxxxxxx> 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 [1] 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. > > By "behaving differently", do you mean internally adapting to the boot > mode, or exhibiting different behaviour to the user? As far as backlight control goes, both. > We have evidence of the firmware behaving differently (VBT, backlight) > based on the boot mode, all else being equal. We don't adapt to that, > and we fail. I don't know if we should adapt, or do things differently > altogether. I don't even know if Windows 8 works on all boot modes on > the machines in question. Sure, but Windows knows nothing about VBT or opregion-backed backlight control. That's up to the Intel driver. -- Matthew Garrett <matthew.garrett@xxxxxxxxxx> _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
