Re: [PATCH 1/2] drm/i915: refactor sink bpp clamping

From: Daniel Vetter <daniel@ffwll.ch>
To: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: Re: [PATCH 1/2] drm/i915: refactor sink bpp clamping
Date: Mon, 3 Jun 2013 11:17:38 +0200	[thread overview]
Message-ID: <20130603091738.GL15743@phenom.ffwll.local> (raw)
In-Reply-To: <1370172384-24026-1-git-send-email-daniel.vetter@ffwll.ch>

On Sun, Jun 02, 2013 at 01:26:23PM +0200, Daniel Vetter wrote:
> As a prep work to fix it up:
> - Use intel_connector instead of drm_connector to avoid too much
>   upcasting in the bugfix patch.
> - Extract the connector bpp clamping from the loop-over-connectors
>   logic.
> - Bikeshed function names (to make it clearer that
>   acompute_baseline_pipe_bpp runs in the compute stage of the modeset
>   sequence) and add a comment to make it clearer what it does.
> 
> No functional change in this patch.

Meh, I've missed that I've added the debug output here. I'll bikeshed the
commit message when applying.
> 
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 63 +++++++++++++++++++++++-------------
>  1 file changed, 41 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index f410ede..6539edb 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7567,13 +7567,39 @@ static void intel_modeset_commit_output_state(struct drm_device *dev)
>  	}
>  }
>  
> +static void
> +connected_sink_compute_bpp(struct intel_connector * connector,
> +			   struct intel_crtc_config *pipe_config)
> +{
> +	int bpp = pipe_config->pipe_bpp;
> +
> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] checking for sink bpp constrains\n",
> +		connector->base.base.id,
> +		drm_get_connector_name(&connector->base));
> +
> +	/* Don't use an invalid EDID bpc value */
> +	if (connector->base.display_info.bpc &&
> +	    connector->base.display_info.bpc * 3 < bpp) {
> +		DRM_DEBUG_KMS("clamping display bpp (was %d) to EDID reported max of %d\n",
> +			      bpp, connector->base.display_info.bpc*3);
> +		pipe_config->pipe_bpp = connector->base.display_info.bpc*3;
> +	}
> +
> +	/* Clamp bpp to 8 on screens without EDID 1.4 */
> +	if (connector->base.display_info.bpc == 0 && bpp > 24) {
> +		DRM_DEBUG_KMS("clamping display bpp (was %d) to default limit of 24\n",
> +			      bpp);
> +		pipe_config->pipe_bpp = 24;
> +	}
> +}
> +
>  static int
> -pipe_config_set_bpp(struct drm_crtc *crtc,
> -		    struct drm_framebuffer *fb,
> -		    struct intel_crtc_config *pipe_config)
> +compute_baseline_pipe_bpp(struct intel_crtc *crtc,
> +			  struct drm_framebuffer *fb,
> +			  struct intel_crtc_config *pipe_config)
>  {
> -	struct drm_device *dev = crtc->dev;
> -	struct drm_connector *connector;
> +	struct drm_device *dev = crtc->base.dev;
> +	struct intel_connector *connector;
>  	int bpp;
>  
>  	switch (fb->pixel_format) {
> @@ -7616,24 +7642,12 @@ pipe_config_set_bpp(struct drm_crtc *crtc,
>  
>  	/* Clamp display bpp to EDID value */
>  	list_for_each_entry(connector, &dev->mode_config.connector_list,
> -			    head) {
> -		if (connector->encoder && connector->encoder->crtc != crtc)
> +			    base.head) {
> +		if (connector->base.encoder &&
> +		    connector->base.encoder->crtc != crtc)
>  			continue;
>  
> -		/* Don't use an invalid EDID bpc value */
> -		if (connector->display_info.bpc &&
> -		    connector->display_info.bpc * 3 < bpp) {
> -			DRM_DEBUG_KMS("clamping display bpp (was %d) to EDID reported max of %d\n",
> -				      bpp, connector->display_info.bpc*3);
> -			pipe_config->pipe_bpp = connector->display_info.bpc*3;
> -		}
> -
> -		/* Clamp bpp to 8 on screens without EDID 1.4 */
> -		if (connector->display_info.bpc == 0 && bpp > 24) {
> -			DRM_DEBUG_KMS("clamping display bpp (was %d) to default limit of 24\n",
> -				      bpp);
> -			pipe_config->pipe_bpp = 24;
> -		}
> +		connected_sink_compute_bpp(connector, pipe_config);
>  	}
>  
>  	return bpp;
> @@ -7714,7 +7728,12 @@ intel_modeset_pipe_config(struct drm_crtc *crtc,
>  	pipe_config->cpu_transcoder = to_intel_crtc(crtc)->pipe;
>  	pipe_config->shared_dpll = DPLL_ID_PRIVATE;
>  
> -	plane_bpp = pipe_config_set_bpp(crtc, fb, pipe_config);
> +	/* Compute a starting value for pipe_config->pipe_bpp taking the source
> +	 * plane pixel format and any sink constraints into account. Returns the
> +	 * source plane bpp so that dithering can be selected on mismatches
> +	 * after encoders and crtc also have had their say. */
> +	plane_bpp = compute_baseline_pipe_bpp(to_intel_crtc(crtc),
> +					      fb, pipe_config);
>  	if (plane_bpp < 0)
>  		goto fail;
>  
> -- 
> 1.7.11.7
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch