Backlight controls work fine when ideapad_laptop is blacklisted, but don't work when it's loaded. root@Paul-Hybrid /sys/kernel/debug/ideapad # cat status Backlight max: 16 Backlight now: 16 BL power value: On ===================== Radio status: On(1) Wifi status: Off(0) BT status: Off(0) 3G status: Off(0) ===================== Touchpad status:On(1) Camera status: On(1) root@Paul-Hybrid /sys/kernel/debug/ideapad # cat cfg cfg: 0x41FDE114 Capability: Bluetooth Wireless Camera Graphic: Intel Note that my backlight was not actually at 16 (100%) when I ran the first command; it was lowered from before I had loaded ideapad_laptop. I've applied this patch to ideapad_laptop.c to fix wifi: https://github.com/torvalds/linux/commit/f71c882dd4cfe4aa88ea07b1402ddd43605d4aef
It appears this was a regression introduced with https://github.com/torvalds/linux/commit/26bff5f099722fa7c38796a3ccd0e880cf1a524a. The logic of the if statement in drivers/platform/x86/ideapad-laptop.c on line 907 was flipped. Changing == to != fixes the issue. I've created a pull request with a patch: https://github.com/torvalds/linux/pull/236
It's worth noting that the "Backlight now" value reported by /sys/kernel/debug/ideapad/status is still always 16; however, I suspect this was the case prior to the regression. "BL power value" also appears to be stuck.