On 01/21/2014 11:17 AM, Matthew Garrett wrote: > On Tue, 2014-01-21 at 10:24 +0800, Aaron Lu wrote: >> On 01/20/2014 09:34 PM, Matthew Garrett wrote: >>> On Mon, 2014-01-20 at 16:12 +0800, Aaron Lu wrote: >>> >>>> 1 remove the win8 OSI check, I've seen win7 laptops that also needs to >>>> have only the GPU interface left and checking win8 doesn't make much >>>> sense now; >>> >>> Are we sure that those aren't simply some other bug? >> >> Well, the firmware on that laptop makes use of EC to do backlight >> control and the fact that the firmware interface doesn't work while the >> GPU's work seems to indicate that the backlight control circuit is not >> routed to EC. I think this is the same case as Win8 laptops. > > We know that Windows 8 graphics drivers don't use the ACPI interface, > and that systems change their behaviour as a result, in some cases with > absolutely no way for the ACPI interface could possibly work. I haven't > seen any cases where that's obviously true for any non-Windows 8 Perhaps I'm not clear, I didn't mean non-Windows 8 systems will all favor GPU's interface, I just meant for one specific win7 laptop I could re-use the existing code to make the GPU's interface as the only one left. And to achieve this, the Win8 OSI check in acpi_video_verify_backlight_support has to be gone. BTW, I actually think use_native_backlight param should mean "the native backlight control interface will be the only one available on the system", it doesn't need to go side by side with Win8 OSI check. > systems. EC interfaces that don't work are often due to Linux leaving > the hardware in a state other than the one expected by the firmware. We Good to know this, thanks. > shouldn't assume that it's the same issue until we've investigated > further. OK, but I honestly don't have any idea how to proceed, in case you have some time, the bug is: https://bugzilla.kernel.org/show_bug.cgi?id=66501 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
