On 07/15/2014 02:56 AM, Julian Wollrath wrote: > Am Mon, 14 Jul 2014 21:10:47 +0200 > schrieb "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>: > >> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote: >>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote: >>>> Am Mon, 14 Jul 2014 20:21:19 +0200 >>>> schrieb "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>: >>>> >>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote: >>>>>> Hi, >>>>>> >>>>>>> changing the brightness on my Thinkpad X230 with Intel >>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe >>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled >>>>>>> default to 0). Changing it back to 1, fixes the problem, if >>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit >>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get >>>>>>> changing the brightness working. >>>>>> >>>>>> small correction: It setting "acpi_osi=!Windows 2012" does >>>>>> only help when using a kernel with commit 886129a8eebe as >>>>>> HEAD, with v3.16-rc4 setting >>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012 >>>>>> or just one of them, does not make changing the brightness >>>>>> work again. >>>>> >>>>> And reverting commit 751109aad583 (ACPI / video: Change the >>>>> default for video.use_native_backlight to 1) make that last >>>>> problem go away, right? >>>>> >>>>> We are going to rever commit 886129a8eebe for other reasons, so >>>>> can you please revert it from 3.16-rc5 on your system and >>>>> report back? >>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing >>>> the brightness works again. >>> >>> What if you revert 886129a8eebe alone? >> >> I mean, what exactly do you need to pass to the kernel command line >> in that case to make brightness switching work? > I need to pass > acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1 > > If I leave one of these parameters out, the brightness switch stops > working. If you only pass the following 2 cmdline options: acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 Will there be the /sys/class/backlight/acpi_videoX file? Thanks, Aaron -- 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
