Hi all, I'm wondering are there any concerns that prevent this patch from entering the upstream? Best regards, AceLan Kao. 2014-08-22 14:18 GMT+08:00 Yidi Lin <yidi.lin@xxxxxxxxxxxxx>: > Hi Karol Babioch, > > On Fri, Aug 22, 2014 at 7:35 AM, Karol Babioch <karol@xxxxxxxxxx> wrote: >> By looking at your description (and your patch) I'm wondering how >> exactly this problem made itself apparent? I'm having a similar (the >> same?) issue with my Sony Vaio VPCS12C5E. The backlight interface >> registered by ACPI does not work and I have to boot with the command >> line option "acpi_backlight=vendor". Even then two interfaces get >> registered "nv_backlight" and "sony", only one of which (nv_backlight) >> works. >> > > My situation is that the brightness control on Lenovo B470e is broken on > Ubuntu 12.04.5 but 12.04.2. Neither "acpi_backlight=vendor " nor > "video.use_native_backlight=1" works for the brightness control. > > After bisecting, the regression happens in 3.10-rc1. > > Before 3.10-rc1, acpi/video.c fails to register backlight interface due to > acpi_video_device_lcd_set_level() returns -EINVAL in > acpi_video_init_brightness(). > Only "intel_backlight" is registered under /sys/class/backlight. > So the brightness can be adjusted from UI. > > In 3.10-rc1, some changes make acpi/video.c able to register backlight > for Lenovo B470e. "acpi_video0" is used as the default backlight interface. > > There is no BIOS update since 2012. And the vendor is unlikely to fix this bug. > So I propose the patch for fixing the brightness control on Lenovo B470e. > >> Desktop environments (GNOME in particular) seem to be confused by this, >> so I always have to change the brightness by writing directly into the >> "actual_brightness" file. I've reported this back in 2012 [1], but was >> told that it is an ACPI issue and so it never was fixed. >> > > Similar situation on Toshiba T130-15T > https://bugzilla.kernel.org/show_bug.cgi?id=50551 > >> Couldn't a similar patch be applied to the sony-laptop module? I've >> added Mattia Dongili to the discussion, hopefully he doesn't mind to >> take a look at this again. I'm glad to test any patches, but am not >> familiar enough with all of the internal structs to mess around with >> them for myself without breaking support for other users of this module, >> especially since my model was shipped with in two different versions: >> One with the internal Intel GPU and another with a dedicated Nvidia GPU. >> I'm afraid a simple DMI match might not be good enough in this case? >> > > You may use dmidecode to see if there is any extra information which can > differentiate between these two versions. > > Regards, > Edward Lin > -- > To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chia-Lin Kao(AceLan) http://blog.acelan.idv.tw/ E-Mail: acelan.kaoATcanonical.com (s/AT/@/) -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
