Re: [PATCH 2/2] drm/i915/dsi: Don't use SET_CONTEXT_LATENCY with DSI transcoders

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

On Mon, 26 Feb 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> ADL DSI transcoders do not have the new SET_CONTEXT_LATENCY
> register. Instead they supposedly use the older TGL VBLANK_START
> based method of defining the vblank delay.
>
> Completely untested due to lack of suitable hardware.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 00ac65a14029..e9c7e9b8957a 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2617,7 +2617,7 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  	 * VBLANK_START no longer works on ADL+, instead we must use
>  	 * TRANS_SET_CONTEXT_LATENCY to configure the pipe vblank start.
>  	 */
> -	if (DISPLAY_VER(dev_priv) >= 13) {
> +	if (DISPLAY_VER(dev_priv) >= 13 && !transcoder_is_dsi(cpu_transcoder)) {
>  		intel_de_write(dev_priv, TRANS_SET_CONTEXT_LATENCY(cpu_transcoder),
>  			       crtc_vblank_start - crtc_vdisplay);

-- 
Jani Nikula, Intel