On Tue, 26 Aug 2014, Daniel Vetter wrote: > On Tue, Aug 26, 2014 at 07:33:25PM +0200, Daniel Vetter wrote: >> Indeed the bios seems to just but gunk into that register. And if we add >> in all the knobs there's piles of them (you have semi-duplicated backlight >> registers on hsw on the PCH), so I guess it doesn't make sense to combine >> them all and warn if something goes awry, at least not in a -fixes patch. >> So Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> on your original >> patch. >> >> Jani can decide whether he wants to save this WARN_ON (imo it's useful to >> have such sanity-checks) in -next by taking all the various bits and duty >> cycles into account. But maybe just on the latest platforms, that still >> should give is good coverage, but with a lot less fuss. > > Out of curiosity: What are the PCH copies of the backlight registers doing > after resume? Thanks Daniel, here's the info: When entering hsw_enable_pc8 during suspend - the physical backlight is off - BLC_PWM_CPU_CTL == 0x 3a90000 (BACKLIGHT_DUTY_CYCLE_MASK == ffff) - BLC_PWM_CPU_CTL2 == 0x60000000 - BLC_PWM_PCH_CTL == 0x 0 - BLC_PWM_PCH_CTL2 == 0x 3a90000 When exiting hsw_disable_pc8 during resume - the physical backlight is off - BLC_PWM_CPU_CTL == 0x 200 - BLC_PWM_CPU_CTL2 == 0x80000000 (BLM_PWM_ENABLE) - BLC_PWM_PCH_CTL == 0x80000000 - BLC_PWM_PCH_CTL2 == 0x 4000000 When entering pch_enable_backlight during resume - the physical backlight is off - BLC_PWM_CPU_CTL == 0x 200 - BLC_PWM_CPU_CTL2 == 0x80000000 - BLC_PWM_PCH_CTL == 0x80000000 - BLC_PWM_PCH_CTL2 == 0x 4000000 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) - BLC_PWM_PCH_CTL == 0x80000000 - BLC_PWM_PCH_CTL2 == 0x 3a90000 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
