[Intel-gfx] [PATCH v2 18/40] drm/i915: Disable pipes in reverse order

[Kahola, Mika]

On Sat, 2019-08-17 at 02:38 -0700, Lucas De Marchi wrote:
> From: José Roberto de Souza <jose.souza at intel.com>
> 
> Disable CRTC/pipes in reverse order because some features (MST in
> TGL+) requires master and slave relationship between pipes, so it
> should always pick the lowest pipe as master as it will be enabled
> first and disable in the reverse order so the master will be the last
> one to be disabled.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>

Reviewed-by: Mika Kahola <mika.kahola at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> b/drivers/gpu/drm/i915/display/intel_display.c
> index b51d1ceb8739..ddb8436e2208 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -13908,7 +13908,15 @@ static void intel_atomic_commit_tail(struct
> intel_atomic_state *state)
>  	if (state->modeset)
>  		wakeref = intel_display_power_get(dev_priv,
> POWER_DOMAIN_MODESET);
>  
> -	for_each_oldnew_intel_crtc_in_state(state, crtc,
> old_crtc_state, new_crtc_state, i) {
> +	/*
> +	 * Disable CRTC/pipes in reverse order because some
> features(MST in
> +	 * TGL+) requires master and slave relationship between pipes,
> so it
> +	 * should always pick the lowest pipe as master as it will be
> enabled
> +	 * first and disable in the reverse order so the master will be
> the
> +	 * last one to be disabled.
> +	 */
> +	for_each_oldnew_intel_crtc_in_state_reverse(state, crtc,
> old_crtc_state,
> +						    new_crtc_state, i)
> {
>  		if (needs_modeset(new_crtc_state) ||
>  		    new_crtc_state->update_pipe) {
>