Re: [PATCH] drm/i915: Parse panel BL controller from VBT

Bob Paauwe
2016-12-07T17:45:55Z

I currently have this same patch in my tree (well with the two changes
below) and have been testing it so with the changes.

Reviewed-by: Bob Paauwe <bob.j.paauwe@intel.com>
Tested-by: Bob Paauwe <bob.j.paauwe@intel.com>

On Wed, 7 Dec 2016 20:32:18 +0530 Vidya Srinivas
<vidya.srinivas@intel.com> wrote:

> Currently the backlight controller is taken as 0. It needs to derive
> value from the VBT. Adding the necessary changes.
>
> v2: Updated the commit header
>
> Signed-off-by: Uma Shankar <uma.shankar@intel.com>
> Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/intel_bios.c | 5 +++++
> drivers/gpu/drm/i915/intel_panel.c | 2 +-
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 8daa4fb..6a85fdf 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1633,6 +1633,7 @@ struct intel_vbt_data {
> bool present;
> bool active_low_pwm;
> u8 min_brightness; /* min_brightness/255 of max */
> + u8 controller; /* brightness controller number */
> enum intel_backlight_type type;
> } backlight;
>
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index eaade27..130db0f 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -330,6 +330,8 @@ static u32 get_blocksize(const void *block_data)
>
> method = &backlight_data->backlight_control[panel_type];
> dev_priv->vbt.backlight.type = method->type;
> + dev_priv->vbt.backlight.controller = 0;

Setting it to zero first seems redundant. Is there a reason you do
this?

> + dev_priv->vbt.backlight.controller = method->controller;
> }
>
> dev_priv->vbt.backlight.pwm_freq_hz = entry->pwm_freq_hz;
> @@ -341,6 +343,9 @@ static u32 get_blocksize(const void *block_data)
> dev_priv->vbt.backlight.active_low_pwm ? "low" : "high",
> dev_priv->vbt.backlight.min_brightness,
> backlight_data->level[panel_type]);
> +
> + DRM_DEBUG_KMS("VBT BL controller %u\n",
> + dev_priv->vbt.backlight.controller);
> }
>
> /* Try to find sdvo panel data */
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index 3578b40..6a7d4c3 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -1612,7 +1612,7 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
> * For BXT hard coding the Backlight controller to 0.
> * TODO : Read the controller value from VBT and generalize
> */
> - panel->backlight.controller = 0;
> + panel->backlight.controller = dev_priv->vbt.backlight.controller;

You should remove the comment above now that it's not hard coded.

>
> pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
>

--
--
Bob Paauwe
Bob.J.Paauwe@intel.com
IOTG / PED Software Organization
Intel Corp. Folsom, CA
(916) 356-6193