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From:   Jani Nikula <jani.nikula@intel.com>
To:     Lyude Paul <lyude@redhat.com>, intel-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Anshuman Gupta <anshuman.gupta@intel.com>,
        Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>,
        David Airlie <airlied@linux.ie>,
        Lucas De Marchi <lucas.demarchi@intel.com>,
        open list <linux-kernel@vger.kernel.org>,
        Chris Wilson <chris@chris-wilson.co.uk>,
        Hans de Goede <hdegoede@redhat.com>,
        Uma Shankar <uma.shankar@intel.com>,
        Sean Paul <seanpaul@chromium.org>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Dave Airlie <airlied@redhat.com>
Subject: Re: [PATCH v7 1/5] drm/i915: Pass port to intel_panel_bl_funcs.get()
In-Reply-To: <20210114221709.2261452-2-lyude@redhat.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
References: <20210114221709.2261452-1-lyude@redhat.com> <20210114221709.2261452-2-lyude@redhat.com>
Date:   Fri, 15 Jan 2021 15:48:23 +0200
Message-ID: <8735z2pazc.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Thu, 14 Jan 2021, Lyude Paul <lyude@redhat.com> wrote:
> In the next commit where we split PWM related backlight functions from
> higher-level backlight functions, we'll want to be able to retrieve the
> backlight level for the current display panel from the
> intel_panel_bl_funcs->setup() function using pwm_funcs->get(). Since
> intel_panel_bl_funcs->setup() is called before we've fully read in the
> current hardware state into our atomic state, we can't grab atomic
> modesetting locks safely anyway in intel_panel_bl_funcs->setup(), and some
> PWM backlight functions (vlv_get_backlight() in particular) require knowing
> the currently used pipe we need to be able to discern the current display
> pipe through other means. Luckily, we're already passing the current
> display pipe to intel_panel_bl_funcs->setup() so all we have to do in order
> to achieve this is pass down that parameter to intel_panel_bl_funcs->get().
>
> So, fix this by accepting an additional pipe parameter in
> intel_panel_bl_funcs->get(), and leave figuring out the current display
> pipe up to the caller.
>
> Signed-off-by: Lyude Paul <lyude@redhat.com>

Much neater than anything I suggested!

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  .../drm/i915/display/intel_display_types.h    |  2 +-
>  .../drm/i915/display/intel_dp_aux_backlight.c |  4 +-
>  .../i915/display/intel_dsi_dcs_backlight.c    |  2 +-
>  drivers/gpu/drm/i915/display/intel_panel.c    | 40 ++++++++-----------
>  4 files changed, 21 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 585bb1edea04..b1f4ec144207 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -228,7 +228,7 @@ struct intel_encoder {
>  struct intel_panel_bl_funcs {
>  	/* Connector and platform specific backlight functions */
>  	int (*setup)(struct intel_connector *connector, enum pipe pipe);
> -	u32 (*get)(struct intel_connector *connector);
> +	u32 (*get)(struct intel_connector *connector, enum pipe pipe);
>  	void (*set)(const struct drm_connector_state *conn_state, u32 level);
>  	void (*disable)(const struct drm_connector_state *conn_state, u32 level);
>  	void (*enable)(const struct intel_crtc_state *crtc_state,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> index 9775f33d1aac..de764dae1e66 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -128,7 +128,7 @@ static bool intel_dp_aux_vesa_backlight_dpcd_mode(struct intel_connector *connec
>   * Read the current backlight value from DPCD register(s) based
>   * on if 8-bit(MSB) or 16-bit(MSB and LSB) values are supported
>   */
> -static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector)
> +static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct intel_dp *intel_dp = intel_attached_dp(connector);
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> @@ -381,7 +381,7 @@ static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector,
>  		return -ENODEV;
>  
>  	panel->backlight.min = 0;
> -	panel->backlight.level = intel_dp_aux_vesa_get_backlight(connector);
> +	panel->backlight.level = intel_dp_aux_vesa_get_backlight(connector, pipe);
>  	panel->backlight.enabled = intel_dp_aux_vesa_backlight_dpcd_mode(connector) &&
>  				   panel->backlight.level != 0;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c b/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> index 88628764956d..584c14c4cbd0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> @@ -43,7 +43,7 @@
>  
>  #define PANEL_PWM_MAX_VALUE		0xFF
>  
> -static u32 dcs_get_backlight(struct intel_connector *connector)
> +static u32 dcs_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct intel_encoder *encoder = intel_attached_encoder(connector);
>  	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index 7a4239d1c241..7587aaefc7a0 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -530,21 +530,21 @@ static u32 intel_panel_compute_brightness(struct intel_connector *connector,
>  	return val;
>  }
>  
> -static u32 lpt_get_backlight(struct intel_connector *connector)
> +static u32 lpt_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  
>  	return intel_de_read(dev_priv, BLC_PWM_PCH_CTL2) & BACKLIGHT_DUTY_CYCLE_MASK;
>  }
>  
> -static u32 pch_get_backlight(struct intel_connector *connector)
> +static u32 pch_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  
>  	return intel_de_read(dev_priv, BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
>  }
>  
> -static u32 i9xx_get_backlight(struct intel_connector *connector)
> +static u32 i9xx_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  	struct intel_panel *panel = &connector->panel;
> @@ -564,23 +564,17 @@ static u32 i9xx_get_backlight(struct intel_connector *connector)
>  	return val;
>  }
>  
> -static u32 _vlv_get_backlight(struct drm_i915_private *dev_priv, enum pipe pipe)
> +static u32 vlv_get_backlight(struct intel_connector *connector, enum pipe pipe)
>  {
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> +
>  	if (drm_WARN_ON(&dev_priv->drm, pipe != PIPE_A && pipe != PIPE_B))
>  		return 0;
>  
>  	return intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe)) & BACKLIGHT_DUTY_CYCLE_MASK;
>  }
>  
> -static u32 vlv_get_backlight(struct intel_connector *connector)
> -{
> -	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> -	enum pipe pipe = intel_connector_get_pipe(connector);
> -
> -	return _vlv_get_backlight(dev_priv, pipe);
> -}
> -
> -static u32 bxt_get_backlight(struct intel_connector *connector)
> +static u32 bxt_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  	struct intel_panel *panel = &connector->panel;
> @@ -589,7 +583,7 @@ static u32 bxt_get_backlight(struct intel_connector *connector)
>  			     BXT_BLC_PWM_DUTY(panel->backlight.controller));
>  }
>  
> -static u32 ext_pwm_get_backlight(struct intel_connector *connector)
> +static u32 ext_pwm_get_backlight(struct intel_connector *connector, enum pipe unused)
>  {
>  	struct intel_panel *panel = &connector->panel;
>  	struct pwm_state state;
> @@ -1233,7 +1227,7 @@ static u32 intel_panel_get_backlight(struct intel_connector *connector)
>  	mutex_lock(&dev_priv->backlight_lock);
>  
>  	if (panel->backlight.enabled) {
> -		val = panel->backlight.funcs->get(connector);
> +		val = panel->backlight.funcs->get(connector, intel_connector_get_pipe(connector));
>  		val = intel_panel_compute_brightness(connector, val);
>  	}
>  
> @@ -1646,9 +1640,9 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus
>  		   !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) &&
>  		   (cpu_ctl2 & BLM_PWM_ENABLE);
>  	if (cpu_mode)
> -		val = pch_get_backlight(connector);
> +		val = pch_get_backlight(connector, unused);
>  	else
> -		val = lpt_get_backlight(connector);
> +		val = lpt_get_backlight(connector, unused);
>  
>  	if (cpu_mode) {
>  		drm_dbg_kms(&dev_priv->drm,
> @@ -1690,7 +1684,7 @@ static int pch_setup_backlight(struct intel_connector *connector, enum pipe unus
>  
>  	panel->backlight.min = get_backlight_min_vbt(connector);
>  
> -	val = pch_get_backlight(connector);
> +	val = pch_get_backlight(connector, unused);
>  	val = intel_panel_compute_brightness(connector, val);
>  	panel->backlight.level = clamp(val, panel->backlight.min,
>  				       panel->backlight.max);
> @@ -1731,7 +1725,7 @@ static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unu
>  
>  	panel->backlight.min = get_backlight_min_vbt(connector);
>  
> -	val = i9xx_get_backlight(connector);
> +	val = i9xx_get_backlight(connector, unused);
>  	val = intel_panel_compute_brightness(connector, val);
>  	panel->backlight.level = clamp(val, panel->backlight.min,
>  				       panel->backlight.max);
> @@ -1765,7 +1759,7 @@ static int i965_setup_backlight(struct intel_connector *connector, enum pipe unu
>  
>  	panel->backlight.min = get_backlight_min_vbt(connector);
>  
> -	val = i9xx_get_backlight(connector);
> +	val = i9xx_get_backlight(connector, unused);
>  	val = intel_panel_compute_brightness(connector, val);
>  	panel->backlight.level = clamp(val, panel->backlight.min,
>  				       panel->backlight.max);
> @@ -1798,7 +1792,7 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
>  
>  	panel->backlight.min = get_backlight_min_vbt(connector);
>  
> -	val = _vlv_get_backlight(dev_priv, pipe);
> +	val = vlv_get_backlight(connector, pipe);
>  	val = intel_panel_compute_brightness(connector, val);
>  	panel->backlight.level = clamp(val, panel->backlight.min,
>  				       panel->backlight.max);
> @@ -1840,7 +1834,7 @@ bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
>  
>  	panel->backlight.min = get_backlight_min_vbt(connector);
>  
> -	val = bxt_get_backlight(connector);
> +	val = bxt_get_backlight(connector, unused);
>  	val = intel_panel_compute_brightness(connector, val);
>  	panel->backlight.level = clamp(val, panel->backlight.min,
>  				       panel->backlight.max);
> @@ -1880,7 +1874,7 @@ cnp_setup_backlight(struct intel_connector *connector, enum pipe unused)
>  
>  	panel->backlight.min = get_backlight_min_vbt(connector);
>  
> -	val = bxt_get_backlight(connector);
> +	val = bxt_get_backlight(connector, unused);
>  	val = intel_panel_compute_brightness(connector, val);
>  	panel->backlight.level = clamp(val, panel->backlight.min,
>  				       panel->backlight.max);

-- 
Jani Nikula, Intel Open Source Graphics Center