On Friday, May 02, 2014 11:32:15 AM Hans de Goede wrote: > Hi All, > > I was already considering asking for $subject for a while, but I did not see > any bug reports caused by it so I didn't ask. Until today I discovered that > I'm not seeing any bugs because Fedora is carrying a kernel patch > changing the default. > > A quick google search for brightness_switch_enabled OTOH reveals that for > other distros it is a serious problem, see ie: > https://bugs.launchpad.net/gnome-settings-daemon/+bug/527157 > http://askubuntu.com/questions/173921/why-does-my-thinkpad-brightness-control-skip-steps > > The problem is that acpi-video is unique in that it not only generates > brightness up/down keypresses, but also (sometimes) actively changes the > brightness itself. > > This presents an inconsistent kernel interface to userspace, basically there > are 2 different scenarios, depending on the laptop model: > > 1) On some laptops a brightness up/down keypress means: show a brightness osd > with the current brightness, iow it is a brightness has changed notification. > > 2) Where as on (a lot of) other laptops it means a brightness up/down key was > pressed, deal with it. > > Most of the desktop environments interpret any press as in scenario 2, and > change the brightness up / down as a response to the key events, causing it > to be changed twice, once by acpi-video and once by the DE. > > With the new default for video.use_native_backlight we will be moving even > more laptops over to behaving as in scenario 2. Making the remaining laptops > even more of a weird exception. Also note that it is hard to detect scenario > 1 properly in userspace, and AFAIK none of the DE-s deasls with it. > > Therefor I would like to propose to change the brightness_switch_enabled > default to 0. Aaron, what do you think about that? -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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
