On Monday, October 24, 2022 9:17 PM, Ville Syrjälä
<ville.syrj...@linux.intel.com> wrote:
>On Mon, Oct 24, 2022 at 02:40:04PM +0800, Lee Shawn C wrote:
>> Driver always apply panel power off cycle delay before eDP enable.
>> If eDP display was enabled at pre-os stage, driver would always
>> trigger modeset to optimize cdclk setting after boot into kernel.
>> So last_power_on and last_backlight_off value will be updated.
>>
>> We can check last_power_on and last_backlight_off before insert panel
>> power cycle delay. If these values are the same, it means eDP was off
>> until now and driver should bypass this delay to save some times to
>> speed up eDP power on sequence.
>>
>> Cc: Shankar Uma <uma.shan...@intel.com>
>> Cc: Jani Nikula <jani.nik...@linux.intel.com>
>> Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
>> Signed-off-by: Lee Shawn C <shawn.c....@intel.com>
>> ---
>> drivers/gpu/drm/i915/display/intel_pps.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_pps.c
>> b/drivers/gpu/drm/i915/display/intel_pps.c
>> index 21944f5bf3a8..f3485a4fbfd0 100644
>> --- a/drivers/gpu/drm/i915/display/intel_pps.c
>> +++ b/drivers/gpu/drm/i915/display/intel_pps.c
>> @@ -509,6 +509,13 @@ static void wait_panel_power_cycle(struct intel_dp
>> *intel_dp)
>> ktime_t panel_power_on_time;
>> s64 panel_power_off_duration;
>>
>> + /* When last_power_on equal to last_backlight_off, it means driver did
>> not
>> + * turn on or off eDP panel so far.
>
>But someone else may have turned it off just before we were handed control, we
>have no idea. The pessimistic estimate is the safe one.
Thanks! It looks to me this situation should not be happpened. Right?
>
>Also I don't understand what this has to do with the story in the comit
>message. In that story you say eDP was already on, so the power cycle delay is
>not relevant at all. /me confused.
>
I will modify commit messages and send patch v2 later.
Best regards,
Shawn
>> So we can bypass power cycle delay to
>> + * save some times here.
>> + */
>> + if (intel_dp->pps.last_power_on == intel_dp->pps.last_backlight_off)
>> + return;
>> +
>> drm_dbg_kms(&i915->drm, "Wait for panel power cycle\n");
>>
>> /* take the difference of current time and panel power off time @@
>> -1098,9 +1105,11 @@ bool intel_pps_have_panel_power_or_vdd(struct
>> intel_dp *intel_dp)
>>
>> static void pps_init_timestamps(struct intel_dp *intel_dp) {
>> + unsigned long tmp_jiffies = jiffies;
>> +
>> intel_dp->pps.panel_power_off_time = ktime_get_boottime();
>> - intel_dp->pps.last_power_on = jiffies;
>> - intel_dp->pps.last_backlight_off = jiffies;
>> + intel_dp->pps.last_power_on = tmp_jiffies;
>> + intel_dp->pps.last_backlight_off = tmp_jiffies;
>> }
>>
>> static void
>> --
>> 2.17.1
>
>--
>Ville Syrjälä
>Intel
>
