[Intel-gfx] [PATCH] drm/i915/skl: port A fuse straps don't work on early SKL steppings

[Damien Lespiau]

On Fri, Mar 06, 2015 at 03:53:32PM -0800, Jesse Barnes wrote:
> So try to enumerate eDP unconditionally in those cases.
> 
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>

That's WaIgnoreDDIAStrap, I assumed it actually worked since my eDP
panel was detected... I see it listed without a stepping check but I
guess you have a good source for that one.

So, maybe with the WaIgnoreDDIAStrap mention:

Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>

-- 
Damien

> ---
>  drivers/gpu/drm/i915/intel_display.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 597c10b..8820e8a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12563,10 +12563,15 @@ static void intel_setup_outputs(struct drm_device *dev)
>  	if (HAS_DDI(dev)) {
>  		int found;
>  
> -		/* Haswell uses DDI functions to detect digital outputs */
> +		/*
> +		 * Haswell uses DDI functions to detect digital outputs.
> +		 * On SKL pre-D0 the strap isn't connected, so we assume
> +		 * it's there.
> +		 */
>  		found = I915_READ(DDI_BUF_CTL_A) & DDI_INIT_DISPLAY_DETECTED;
>  		/* DDI A only supports eDP */
> -		if (found)
> +		if (found ||
> +		    (IS_SKYLAKE(dev) && INTEL_REVID(dev) < SKL_REVID_D0))
>  			intel_ddi_init(dev, PORT_A);
>  
>  		/* DDI B, C and D detection is indicated by the SFUSE_STRAP
> -- 
> 1.9.1
> 
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