On 06/18/2013 08:13 AM, Aaron Lu wrote: > On 06/18/2013 06:40 AM, Matthew Garrett wrote: >> On Mon, Jun 17, 2013 at 09:01:10AM +0800, Aaron Lu wrote: >>> Starting from win8, MS backlight control driver will set bit 2 of the >>> parameter of control method _DOS, to inform firmware it should not >>> perform any automatic brightness changes. This mostly affects hotkey >>> notification deliver - if we do not set this bit, on hotkey press, >>> firmware may choose to adjust brightness level instead of sending out >>> notification and doing nothing. >> >> It's worth noting that this is a change in behaviour, and there's at >> least one VIA-based netbook where making this change breaks backlight >> control. > > Thanks for pointing this out. > Do you have any more information about this system, like its ACPI dump? > > BTW, perhaps we should make this behavior change only for win8 systems? Just checked all affected systems: https://bugzilla.kernel.org/show_bug.cgi?id=51051 https://bugzilla.kernel.org/show_bug.cgi?id=56711 https://bugzilla.kernel.org/show_bug.cgi?id=52951 All systems claim win8 in _OSI, so I suppose I'll make this behavior change only for those systems with the help of the recently proposed "Expose OSI version" patchset. Please let me know if you disagree, thanks. -Aaron -- 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
