On 07/15/2014 10:05 PM, Hans de Goede wrote: > Hi, > > On 07/15/2014 02:27 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? > > No, just no, clearly using the acpi video interface for backlight control > is the wrong thing to do on win8 generation laptops, if we don't flip > the default we're going to end up with a never ending list of quirks > for models where the acpi-video interface is broken. > > On 07/15/2014 04:00 PM, Aaron Lu wrote: > > > If we have to consider the following config: > > 1 ACPI backlight interface works(or can work with some cmdline option); > > And the BIOS advertises native win8 support. Right. So this condition should be: 1 ACPI backlight interface works in Win8 mode; This means, for Julian's system, the commit 751109aad583 doesn't need to be reverted as the ACPI backlight interface on his system only works when the acpi_osi="!Windows 2012" is added. In that case, the video.use_native_backlight=X doesn't make any difference anymore. Thanks, Aaron > > > 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. > > I think the combination of 1 and 2 makes the subset of users > potentially affected by this so small, that we really should > continue with video.use_native_backlight=1 as default, the > other route adding more and more and more and more quirks > is sheer madness. > > Regards, > > Hans > > > -- 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
