[Intel-gfx] [PATCH 23/23] drm/i915: WARN about invalid lane reversal in TBT-alt/DP-alt modes

[Souza, Jose]

On Tue, 2019-06-04 at 17:58 +0300, Imre Deak wrote:
> Lane reversal happens only in the FIA module for TBT-alt/DP-alt mode,
> so
> WARN if lane reversal is attempted at a different level. See the
> BSpec DDI_BUF_CTL register description.

Reviewed-by: José Roberto de Souza <jose.souza at intel.com>

> 
> Cc: Manasi Navare <manasi.d.navare at intel.com>
> Cc: José Roberto de Souza <jose.souza at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> b/drivers/gpu/drm/i915/intel_ddi.c
> index 9c198f1a3a91..5f535f17d7b3 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -3591,6 +3591,8 @@ static void intel_ddi_set_fia_lane_count(struct
> intel_encoder *encoder,
>  	u32 val = I915_READ(PORT_TX_DFLEXDPMLE1);
>  	bool lane_reversal = dig_port->saved_port_bits &
> DDI_BUF_PORT_REVERSAL;
>  
> +	WARN_ON(lane_reversal && dig_port->tc_mode != TC_PORT_LEGACY);
> +
>  	val &= ~DFLEXDPMLE1_DPMLETC_MASK(tc_port);
>  	switch (pipe_config->lane_count) {
>  	case 1: