[Intel-gfx] [PATCH] drm/i915: Refine eDP aux backlight enable sequence.

[Lee, Shawn C]

On Thu, 13 Jun 2019, Jani Nikula <jani.nikula at intel.com> wrote:
>On Thu, 13 Jun 2019, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
>> On Wed, Jun 12, 2019 at 10:47:22PM -0700, Lee, Shawn C wrote:
>>> Modify aux backlight enable sequence just like what we did for 
>>> genernal eDP panel.
>>> 1. Setup PWM freq and brightness level before enable display backlight.
>>> 2. Add T8 (valid data to backlight enable) delay.
>>
>> If we respect the on_delay shouldn't we then respect the off_delay too?
>>
>> In which case I suggest two patches:
>> 1. swaap the enable vs. set_brightness order 2. add the on/off delays
>
>The aux backlight functions are called via the same hooks as everything in intel_panel.c, which do not have delays (they're all on the calling side in intel_dp.c) so I'm confused why these would require the delays.
>
>BR,
>Jani.

Refer to intel_edp_backlight_on(). PWM was restored at the end of intel_panel_enable_backlight().
After that, driver would wait for some delay wait_backlight_on() before enable backlight. 

Thanks for Ville's recommendation. I will send separate for this change.

Best regards,
Shawn

>>> 
>>> Cc: Jani Nikula <jani.nikula at intel.com>
>>> Cc: Jose Roberto de Souza <jose.souza at intel.com>
>>> Cc: Cooper Chiou <cooper.chiou at intel.com>
>>> 
>>> Signed-off-by: Lee, Shawn C <shawn.c.lee at intel.com>
>>> ---
>>>  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 6 +++++-
>>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
>>> b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
>>> index 7ded95a334db..c112e0b930de 100644
>>> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
>>> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
>>> @@ -216,8 +216,12 @@ static void intel_dp_aux_enable_backlight(const struct intel_crtc_state *crtc_st
>>>  		}
>>>  	}
>>>  
>>> -	set_aux_backlight_enable(intel_dp, true);
>>>  	intel_dp_aux_set_backlight(conn_state,
>>> connector->panel.backlight.level);
>>> +
>>> +	wait_remaining_ms_from_jiffies(intel_dp->last_power_on,
>>> +				       intel_dp->backlight_on_delay);
>>> +
>>> +	set_aux_backlight_enable(intel_dp, true);
>>>  }
>>>  
>>>  static void intel_dp_aux_disable_backlight(const struct 
>>> drm_connector_state *old_conn_state)
>>> --
>>> 2.7.4
>>> 
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>>> Intel-gfx at lists.freedesktop.org
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>
>--
>Jani Nikula, Intel Open Source Graphics Center