Re: [PATCH 10/13] drm/i915: gather backlight information at setup

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 13 Nov 2013, Imre Deak <imre.deak@intel.com> wrote:
> On Fri, 2013-11-08 at 16:49 +0200, Jani Nikula wrote:
>> Prepare for being able to use the information at enable.
>> 
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_drv.h   |    2 ++
>>  drivers/gpu/drm/i915/intel_panel.c |   68 +++++++++++++++++++++++++++++-------
>>  2 files changed, 58 insertions(+), 12 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> index 7384a7b..6f2bc82 100644
>> --- a/drivers/gpu/drm/i915/intel_drv.h
>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>> @@ -163,6 +163,8 @@ struct intel_panel {
>>  		u32 level;
>>  		u32 max;
>>  		bool enabled;
>> +		bool combination_mode;	/* gen 2/4 only */
>> +		bool active_low_pwm;
>>  		struct backlight_device *device;
>>  	} backlight;
>>  };
>> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
>> index 3dd9f57d..0e8f0a3 100644
>> --- a/drivers/gpu/drm/i915/intel_panel.c
>> +++ b/drivers/gpu/drm/i915/intel_panel.c
>> @@ -490,13 +490,14 @@ static u32 i9xx_get_backlight(struct intel_connector *connector)
>>  {
>>  	struct drm_device *dev = connector->base.dev;
>>  	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	struct intel_panel *panel = &connector->panel;
>>  	u32 val;
>>  
>>  	val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
>>  	if (INTEL_INFO(dev)->gen < 4)
>>  		val >>= 1;
>>  
>> -	if (is_backlight_combination_mode(dev)) {
>> +	if (panel->backlight.combination_mode) {
>>  		u8 lbpc;
>>  
>>  		pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
>> @@ -558,7 +559,7 @@ static void i9xx_set_backlight(struct intel_connector *connector, u32 level)
>>  
>>  	WARN_ON(panel->backlight.max == 0);
>>  
>> -	if (is_backlight_combination_mode(dev)) {
>> +	if (panel->backlight.combination_mode) {
>>  		u8 lbpc;
>>  
>>  		lbpc = level * 0xfe / panel->backlight.max + 1;
>> @@ -966,46 +967,84 @@ static void intel_backlight_device_unregister(struct intel_connector *connector)
>>   */
>>  static int pch_setup_backlight(struct intel_connector *connector)
>>  {
>> +	struct drm_device *dev = connector->base.dev;
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>>  	struct intel_panel *panel = &connector->panel;
>> -	u32 val;
>> +	u32 cpu_ctl2, pch_ctl1, pch_ctl2, val;
>>  
>> -	panel->backlight.max = pch_get_max_backlight(connector);
>> +	pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1);
>> +	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
>> +
>> +	pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
>> +	panel->backlight.max = pch_ctl2 >> 16;
>>  	if (!panel->backlight.max)
>>  		return -ENODEV;
>>  
>>  	val = pch_get_backlight(connector);
>>  	panel->backlight.level = intel_panel_compute_brightness(connector, val);
>>  
>> +	cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
>> +	panel->backlight.enabled = (cpu_ctl2 & BLM_PWM_ENABLE) &&
>> +		(pch_ctl1 & BLM_PCH_PWM_ENABLE) && panel->backlight.level != 0;
>
> Don't we need to check here for QUIRK_NO_PCH_PWM_ENABLE?

Up front, I think the quirk is bogus, and it breaks machines.

Even if *we* don't set BLM_PCH_PWM_ENABLE on quirked machines, we just
expect the BIOS to have done it. So for checking whether the backlight
is enabled, this should be accurate.

BR,
Jani.


>
> --Imre
>
>> +
>>  	return 0;
>>  }
>>  
>>  static int i9xx_setup_backlight(struct intel_connector *connector)
>>  {
>> +	struct drm_device *dev = connector->base.dev;
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>>  	struct intel_panel *panel = &connector->panel;
>> -	u32 val;
>> +	u32 ctl, val;
>> +
>> +	ctl = I915_READ(BLC_PWM_CTL);
>> +
>> +	if (IS_GEN2(dev))
>> +		panel->backlight.combination_mode = ctl & BLM_LEGACY_MODE;
>> +
>> +	if (IS_PINEVIEW(dev))
>> +		panel->backlight.active_low_pwm = ctl & BLM_POLARITY_PNV;
>> +
>> +	panel->backlight.max = ctl >> 17;
>> +	if (panel->backlight.combination_mode)
>> +		panel->backlight.max *= 0xff;
>>  
>> -	panel->backlight.max = i9xx_get_max_backlight(connector);
>>  	if (!panel->backlight.max)
>>  		return -ENODEV;
>>  
>>  	val = i9xx_get_backlight(connector);
>>  	panel->backlight.level = intel_panel_compute_brightness(connector, val);
>>  
>> +	panel->backlight.enabled = panel->backlight.level != 0;
>> +
>>  	return 0;
>>  }
>>  
>>  static int i965_setup_backlight(struct intel_connector *connector)
>>  {
>> +	struct drm_device *dev = connector->base.dev;
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>>  	struct intel_panel *panel = &connector->panel;
>> -	u32 val;
>> +	u32 ctl, ctl2, val;
>> +
>> +	ctl2 = I915_READ(BLC_PWM_CTL2);
>> +	panel->backlight.combination_mode = ctl2 & BLM_COMBINATION_MODE;
>> +	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
>> +
>> +	ctl = I915_READ(BLC_PWM_CTL);
>> +	panel->backlight.max = ctl >> 16;
>> +	if (panel->backlight.combination_mode)
>> +		panel->backlight.max *= 0xff;
>>  
>> -	panel->backlight.max = i965_get_max_backlight(connector);
>>  	if (!panel->backlight.max)
>>  		return -ENODEV;
>>  
>>  	val = i9xx_get_backlight(connector);
>>  	panel->backlight.level = intel_panel_compute_brightness(connector, val);
>>  
>> +	panel->backlight.enabled = (ctl2 & BLM_PWM_ENABLE) &&
>> +		panel->backlight.level != 0;
>> +
>>  	return 0;
>>  }
>>  
>> @@ -1015,7 +1054,7 @@ static int vlv_setup_backlight(struct intel_connector *connector)
>>  	struct drm_i915_private *dev_priv = dev->dev_private;
>>  	struct intel_panel *panel = &connector->panel;
>>  	enum pipe pipe;
>> -	u32 val;
>> +	u32 ctl, ctl2, val;
>>  
>>  	for_each_pipe(pipe) {
>>  		u32 cur_val = I915_READ(VLV_BLC_PWM_CTL(pipe));
>> @@ -1029,13 +1068,20 @@ static int vlv_setup_backlight(struct intel_connector *connector)
>>  			   cur_val);
>>  	}
>>  
>> -	panel->backlight.max = _vlv_get_max_backlight(dev, PIPE_A);
>> +	ctl2 = I915_READ(VLV_BLC_PWM_CTL2(PIPE_A));
>> +	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
>> +
>> +	ctl = I915_READ(VLV_BLC_PWM_CTL(PIPE_A));
>> +	panel->backlight.max = ctl >> 16;
>>  	if (!panel->backlight.max)
>>  		return -ENODEV;
>>  
>>  	val = _vlv_get_backlight(dev, PIPE_A);
>>  	panel->backlight.level = intel_panel_compute_brightness(connector, val);
>>  
>> +	panel->backlight.enabled = (ctl2 & BLM_PWM_ENABLE) &&
>> +		panel->backlight.level != 0;
>> +
>>  	return 0;
>>  }
>>  
>> @@ -1059,8 +1105,6 @@ int intel_panel_setup_backlight(struct drm_connector *connector)
>>  		return ret;
>>  	}
>>  
>> -	panel->backlight.enabled = panel->backlight.level != 0;
>> -
>>  	intel_backlight_device_register(intel_connector);
>>  
>>  	panel->backlight.present = true;
>

-- 
Jani Nikula, Intel Open Source Technology Center