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 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 shouldn't assume that it's the same issue until we've investigated further.