[Intel-gfx] [PATCH] drm/i915/dp: Skip the HW readout of DPCD on disabled encoders

[Souza, Jose]

On Fri, 2021-10-15 at 15:10 +0300, Imre Deak wrote:
> Reading out the DP encoders' DPCD during booting or resume is only
> required for enabled encoders: such encoders may be modesetted during
> the initial commit and the link training this involves depends on an
> initialized DPCD. For DDI encoders reading out the DPCD is skipped, do
> the same on pre-DDI platforms.

Missing fixes tag

> 
> Cc: José Roberto de Souza <jose.souza at intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 9d8132dd4cc5a..23de500d56b52 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2007,6 +2007,9 @@ void intel_dp_sync_state(struct intel_encoder *encoder,
>  {
>  	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>  
> +	if (!crtc_state)
> +		return;

crtc_state is not used

> +
>  	/*
>  	 * Don't clobber DPCD if it's been already read out during output
>  	 * setup (eDP) or detect.