Re: [PATCH 2/2] drm/i915: LVDS fallback to fixed-mode if EDID not present

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 21 Nov 2012, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> Use the recorded panel fixed-mode to populate the get_modes() request in
> the absence of an EDID.
>
> Fixes regression from
> commit 9cd300e038d492af4990b04e127e0bd2df64b1ca
> Author: Jani Nikula <jani.nikula@intel.com>
> Date:   Fri Oct 19 14:51:52 2012 +0300
>
>     drm/i915: Move cached EDID to intel_connector
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/intel_lvds.c |    9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> index 5b38c17..189390e 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -480,13 +480,8 @@ static int intel_lvds_get_modes(struct drm_connector *connector)
>  	struct drm_display_mode *mode;
>  
>  	/* use cached edid if we have one */
> -	if (lvds_connector->base.edid) {
> -		/* invalid edid */
> -		if (IS_ERR(lvds_connector->base.edid))
> -			return 0;
> -
> +	if (!IS_ERR_OR_NULL(lvds_connector->base.edid))
>  		return drm_add_edid_modes(connector, lvds_connector->base.edid);
> -	}

Yeah, good catch, my bad. I guess I was pressing too hard to have
similar code in DP and LVDS...

>  
>  	mode = drm_mode_duplicate(dev, lvds_connector->base.panel.fixed_mode);
>  	if (mode == NULL)
> @@ -1065,8 +1060,6 @@ bool intel_lvds_init(struct drm_device *dev)
>  			kfree(edid);
>  			edid = ERR_PTR(-EINVAL);
>  		}
> -	} else {
> -		edid = ERR_PTR(-ENOENT);

I'd like to keep this though. I was thinking a more generic, future EDID
caching feature might use the difference between -EINVAL and -ENOENT,
NULL being the "we just haven't read it yet" flag, to prevent trying to
re-read the EDID when it isn't there. *shrug*. Either way,

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


>  	}
>  	lvds_connector->base.edid = edid;
>  
> -- 
> 1.7.10.4