On Fri, Apr 6, 2012 at 4:34 PM, Seth Forshee <seth.forshee@xxxxxxxxxxxxx> wrote: > On Fri, Apr 06, 2012 at 11:42:18AM +0200, Corentin Chary wrote: >> On Tue, Mar 27, 2012 at 1:21 PM, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote: >> > On Tue, Mar 27, 2012 at 11:11:18AM +0200, Corentin Chary wrote: >> >> Matthew, is this one ok ? I really hope this patch can go in 3.4 so we >> >> don't introduce a regression for old laptops. >> > >> > Yes, I've got this now. >> > >> > Thanks, >> >> >> A user just found a DSDT which is broken by this way of doing things >> (this is not really a regression since it was also broken before). >> >> _BCL contains a wierd "Or (VDRV, 0x02, VDRV)". >> So if you call _BLC once (video.ko will), it set a flag that affect >> the behavior of all backlight related stuff, and it breaks >> samsung-laptop's backlight even if samsung-laptop unload the acpi >> backlight. >> Using acpi_backlight=vendor solves that since it prevents the module >> from being loaded. My previous patch also fix that since it use >> acpi_backlight= mechanism. >> >> Do you think using acpi_backlight=vendor is a good enought solution >> here ? Should we use my first patch instead ? > > I've recently noticed another problem with using acpi_video_unregister() > to disable known broken backlights -- another module might call > acpi_video_register() and make it reappear. i915 does this, so when I > EFI boot the MacBook Pro 8,2 the acpi backlights reappear (under a BIOS > compatible boot the Intel GPU doesn't show up on the bus). > > So Corentin's solution does seem like a better way to go, or else > something similar that forces the ACPI video driver to behave as with > acpi_video=vendor. > > Seth > Matthew, Len, any input on that ? Should we keep the current code even if broken with some (also broken) hardware or should we move the blacklist in acpi/video.c ? -- Corentin Chary http://xf.iksaif.net -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
