Re: [PATCH] drm/i915: enable vdd when switching off the eDP panel

[Daniel Vetter <daniel@ffwll.ch>]

Hi Keith&Chris,

This is the patch for you to try on the macbook airs ....

Thanks, Daniel

On Sun, May 20, 2012 at 05:14:50PM +0200, Daniel Vetter wrote:
> We have one bug report from a validation team that we get the eDP
> panel sequencing still somewhat wrong: We need to enable VDD while
> switching off the panel and backlight. Unfortunately that reporter
> seems to have fallen off the earth :(
> 
> For another reporter this actually fixes a black panel issue because
> without this the backlight/panel gets confused and doesn't light up
> again.
> 
> v2: I've forgotten to remove the vdd_off call in panel_off which is
> now bogus. This essentially reverts
> 
> commit 17038de5f16569a25343cf68668f3b657eafb00e
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date:   Mon Apr 16 22:43:42 2012 +0100
> 
>     drm/i915/dp: Flush any outstanding work to turn the VDD off
> 
> v3: the current panel_off code forces off the vdd power, too. Which is
> bogus and resulted in some funny warnings later on when we've tried to
> do aux channel communications with just the vdd forced on. Fix this,
> too.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=46312
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43163
> Tested-by: Vincent Frentzel <zcecc22@gmail.com>
> Cc: stable@kernel.org
> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |   18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index a1a5ce7..3bbd754 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1154,11 +1154,10 @@ static void ironlake_edp_panel_off(struct intel_dp *intel_dp)
>  
>  	DRM_DEBUG_KMS("Turn eDP power off\n");
>  
> -	WARN(intel_dp->want_panel_vdd, "Cannot turn power off while VDD is on\n");
> -	ironlake_panel_vdd_off_sync(intel_dp); /* finish any pending work */
> +	WARN(!intel_dp->want_panel_vdd, "Need VDD to turn off panel\n");
>  
>  	pp = ironlake_get_pp_control(dev_priv);
> -	pp &= ~(POWER_TARGET_ON | EDP_FORCE_VDD | PANEL_POWER_RESET | EDP_BLC_ENABLE);
> +	pp &= ~(POWER_TARGET_ON | PANEL_POWER_RESET | EDP_BLC_ENABLE);
>  	I915_WRITE(PCH_PP_CONTROL, pp);
>  	POSTING_READ(PCH_PP_CONTROL);
>  
> @@ -1266,18 +1265,16 @@ static void intel_dp_prepare(struct drm_encoder *encoder)
>  {
>  	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>  
> +
> +	/* Make sure the panel is off before trying to change the mode. But also
> +	 * ensure that we have vdd while we switch off the panel. */
> +	ironlake_edp_panel_vdd_on(intel_dp);
>  	ironlake_edp_backlight_off(intel_dp);
>  	ironlake_edp_panel_off(intel_dp);
>  
> -	/* Wake up the sink first */
> -	ironlake_edp_panel_vdd_on(intel_dp);
>  	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
>  	intel_dp_link_down(intel_dp);
>  	ironlake_edp_panel_vdd_off(intel_dp, false);
> -
> -	/* Make sure the panel is off before trying to
> -	 * change the mode
> -	 */
>  }
>  
>  static void intel_dp_commit(struct drm_encoder *encoder)
> @@ -1309,10 +1306,11 @@ intel_dp_dpms(struct drm_encoder *encoder, int mode)
>  	uint32_t dp_reg = I915_READ(intel_dp->output_reg);
>  
>  	if (mode != DRM_MODE_DPMS_ON) {
> +		/* Switching the panel off requires vdd. */
> +		ironlake_edp_panel_vdd_on(intel_dp);
>  		ironlake_edp_backlight_off(intel_dp);
>  		ironlake_edp_panel_off(intel_dp);
>  
> -		ironlake_edp_panel_vdd_on(intel_dp);
>  		intel_dp_sink_dpms(intel_dp, mode);
>  		intel_dp_link_down(intel_dp);
>  		ironlake_edp_panel_vdd_off(intel_dp, false);
> -- 
> 1.7.10
> 

-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48