[Intel-gfx] [PATCH] KMS: cache the EDID information of the LVDS

[Jesse Barnes]

On Mon, 23 Mar 2009 13:48:33 -0700
Arjan van de Ven <arjan at infradead.org> wrote:

> >From eb512d6d953c8acc8abe1048862a92cec58d9791 Mon Sep 17 00:00:00
> >2001
> From: Arjan van de Ven <arjan at linux.intel.com>
> Date: Mon, 23 Mar 2009 13:38:49 -0700
> Subject: [PATCH] KMS: cache the EDID information of the LVDS
> 
> you're not going to replace your LVDS at runtime..... so this patch
> caches the EDID information of the LVDS. An LVDS probe can easily take
> 200 milliseconds, and we do this multiple times during a system
> startup.
> 
> Signed-off-by: Arjan van de Ven <arjan at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_drv.h   |    1 +
>  drivers/gpu/drm/i915/intel_lvds.c  |    2 ++
>  drivers/gpu/drm/i915/intel_modes.c |    8 +++++++-
>  3 files changed, 10 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h index 957daef..22a74bd 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -81,6 +81,7 @@ struct intel_output {
>  	int type;
>  	struct intel_i2c_chan *i2c_bus; /* for control functions */
>  	struct intel_i2c_chan *ddc_bus; /* for DDC only stuff */
> +	struct edid *edid;
>  	bool load_detect_temp;
>  	bool needs_tv_clock;
>  	void *dev_priv;
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c
> b/drivers/gpu/drm/i915/intel_lvds.c index 0d211af..dc4fecc 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -336,6 +336,7 @@ static void intel_lvds_destroy(struct
> drm_connector *connector) intel_i2c_destroy(intel_output->ddc_bus);
>  	drm_sysfs_connector_remove(connector);
>  	drm_connector_cleanup(connector);
> +	kfree(intel_output->edid);
>  	kfree(connector);
>  }
>  
> @@ -516,5 +517,6 @@ failed:
>  	if (intel_output->ddc_bus)
>  		intel_i2c_destroy(intel_output->ddc_bus);
>  	drm_connector_cleanup(connector);
> +	kfree(intel_output->edid);
>  	kfree(connector);
>  }
> diff --git a/drivers/gpu/drm/i915/intel_modes.c
> b/drivers/gpu/drm/i915/intel_modes.c index e42019e..83816a4 100644
> --- a/drivers/gpu/drm/i915/intel_modes.c
> +++ b/drivers/gpu/drm/i915/intel_modes.c
> @@ -70,13 +70,19 @@ int intel_ddc_get_modes(struct intel_output
> *intel_output) struct edid *edid;
>  	int ret = 0;
>  
> +	if (intel_output->edid)
> +		return ret;
> +
>  	edid = drm_get_edid(&intel_output->base,
>  			    &intel_output->ddc_bus->adapter);
>  	if (edid) {
>  		drm_mode_connector_update_edid_property(&intel_output->base,
>  							edid);
>  		ret = drm_add_edid_modes(&intel_output->base, edid);
> -		kfree(edid);
> +		if (intel_output->type == INTEL_OUTPUT_LVDS)
> +			intel_output->edid = edid;
> +		else
> +			kfree(edid);
>  	}
>  
>  	return ret;

I definitely like the idea of caching the LVDS EDID, but rather than
adding it to the intel_output struct I'd rather see it stored with the
rest of the LVDS stuff in i915_private (though that stuff should be
pulled out into an output private at some point).  We could also just
open code the intel_ddc_get_modes stuff in intel_lvds_init, getting the
EDID just once, storing the property once, and adding the mode list
once.  intel_lvds_get_modes would need to be fixed too...

-- 
Jesse Barnes, Intel Open Source Technology Center