On Tue, 26 Aug 2014, Daniel Vetter wrote: > On Thu, Aug 21, 2014 at 07:12:59AM +0000, Scot Doyle wrote: >> When we enter intel_modeset_setup_hw_state during resume >> - BLC_PWM_CPU_CTL2 == BLM_PWM_ENABLE >> - the physical backlight is off > > Hm, this is actually interesting - we have some other evidence that the > best way to shut off the backlight is actually to just set the pwm duty > cycle to 0. Can you please check that this is the case for your system? /sys/class/backlight/intel_backlight/brightness 0 -> backlight not visible 1 -> backlight visible 937 -> max backlight Setting /sys/class/backlight/intel_backlight/brightness to 0 updates BLC_PWM_CPU_CTL, but BLC_PWM_CPU_CTL2 remains 0xe0000000. > Maybe we just need to extend the check to look for !PWM_ENABLE || > duty_cycle == 0. The following measurements hold true no matter the duty cycle before suspend: When entering hsw_enable_pc8 during suspend - the physical backlight is off - BLC_PWM_CPU_CTL == 0x3a900000 (BACKLIGHT_DUTY_CYCLE_MASK == ffff) - BLC_PWM_CPU_CTL2 == 0x60000000 (BLM_PWM_ENABLE) When exiting hsw_disable_pc8 during resume - the physical backlight is off - BLC_PWM_CPU_CTL == 0x200 - BLC_PWM_CPU_CTL2 == 0x80000000 (BLM_PWM_ENABLE | BLM_TRANSCODER_EDP) When entering pch_enable_backlight during resume - the physical backlight is off - BLC_PWM_CPU_CTL == 0x200 - BLC_PWM_CPU_CTL2 == 0x80000000 (BLM_PWM_ENABLE) When exiting pch_enable_backlight during resume - the physical backlight is off - BLC_PWM_CPU_CTL == duty cycle prior to suspend - BLC_PWM_CPU_CTL2 == 0xe0000000 (BLM_PWM_ENABLE | BLM_TRANSCODER_EDP) So the BIOS is setting BLC_PWM_CPU_CTL=0x200 and BLC_PWM_CPU_CTL2=0x80000000 ? _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
