[Intel-gfx] [v3] drm/i915/pps: improve eDP power on flow

[Jani Nikula]

On Thu, 03 Nov 2022, Lee Shawn C <shawn.c.lee at intel.com> wrote:
> After i915 dirver initialized, a panel power off cycle delay
> always append before turn eDP on. If eDP display did not
> power on before. With this change, power off duration might
> longer than power cycle delay. So driver can save power cycle
> delay to speed up driver initialization time.
>
> v2: fix commit messages
> v3: refine panel_power_off_time default value and modify
>     commit messages
>
> Cc: Shankar Uma <uma.shankar at intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Lee Shawn C <shawn.c.lee at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_pps.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
> index 21944f5bf3a8..a394bb1c92d0 100644
> --- a/drivers/gpu/drm/i915/display/intel_pps.c
> +++ b/drivers/gpu/drm/i915/display/intel_pps.c
> @@ -1098,7 +1098,7 @@ bool intel_pps_have_panel_power_or_vdd(struct intel_dp *intel_dp)
>  
>  static void pps_init_timestamps(struct intel_dp *intel_dp)
>  {
> -	intel_dp->pps.panel_power_off_time = ktime_get_boottime();
> +	intel_dp->pps.panel_power_off_time = 0;

So this is just copy-paste from [1] where we discuss the problems with
this approach, specifically module reload ignoring the power off
time. Why would you post this without even mentioning the problem?


BR,
Jani.


[1] https://gitlab.freedesktop.org/drm/intel/-/issues/7417#note_1619118

>  	intel_dp->pps.last_power_on = jiffies;
>  	intel_dp->pps.last_backlight_off = jiffies;
>  }

-- 
Jani Nikula, Intel Open Source Graphics Center