On Mon, Jul 29, 2013 at 10:11 PM, Aaron Lu <aaron.lwe@xxxxxxxxx> wrote: > On 07/30/2013 03:20 AM, Felipe Contreras wrote: >> Since v3.7 the acpi backlight driver doesn't work at all on this machine >> because presumably the ACPI code contains stub code when Windows 8 OSI is >> reported. >> >> The commit ea45ea7 (in v3.11-rc2) tried to fix this problem by using the intel >> backlight driver, however, on this machine it turns the backlight completely >> off when it reaches level 0%, after which the user might have a lot trouble >> trying to bring it back. > > What do you mean by a lot of trouble? If you press hotkey to increase > backlight brightness level, does it work? I guess so, *if* there is indeed a user-space power manager handling that, *and* the keyboard has such keys, *or* the user has set custom hotkeys. > If so, the screen should not > be black any more, it's not that user has to blindly enter some command > to get out of the black screen. > > And I'm not sure if this is a bug of intel_backlight(setting a low level > makes the screen almost off), I see different models with different > vendors having this behavior. I mean, the screen is completely off, I cannot see absolutely anything. I don't see this behavior with the ACPI backlight driver, nor do I see that in Windows 7. > If this is deemed a bug, then I'm afraid > intel_backlight interface is useless for a lot of systems...perhaps we > can only say, intel_backlight's interpretation of low levels are > different with ACPI video's, and that's probably why its type is named > as raw :-) Well, a bug is defined as unexpected behavior -- as a user, if I'm changing the brightness of the screen, I certainly don't expect the screen to turn off, and I think that's the expectation from most people. It's the first time I see something like that. -- Felipe Contreras -- 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
