On 07/15/2014 08:27 PM, Rafael J. Wysocki wrote: > On Tuesday, July 15, 2014 02:06:21 PM Aaron Lu wrote: >> On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote: >>> On Monday, July 14, 2014 08:56:29 PM 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. >>> >>> With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1. >>> >>> Aaron, what do you think? >> >> I agree. >> >> I suppose Julian is not using an standard GUI so he needs the in kernel >> processing of the backlight event. And his laptop has a broken ACPI >> interface in Win8 mode, so he also needs the "!Windows 2012" option. >> >> With a standard GUI environment, his system would have only one >> interface left: the GPU one and everything should work. But of course, >> that may not be his config. > > Well, do we need to revert 751109aad583 too, then? > > It seems that it may break other systems without a desktop environment, may it not? If we have to consider the following config: 1 ACPI backlight interface works(or can work with some cmdline option); 2 Not using a normal GUI(depends on ACPI video module to do the in kernel backlight level change on hotkey press). Then we will need to revert 751109aad583. 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
