[Intel-gfx] [PATCH 1/7] drm/i915/hsw+: set intel_crtc active once pipe is active

[Zanoni, Paulo R]

Em Seg, 2016-08-29 às 18:05 +0530, Kumar, Mahesh escreveu:
> Set the intel_crtc->active flag after pipe/crtc is actually active in
> haswell_crtc_enable function.

Why?

Can you please elaborate more on why this change is needed, what are
the benefits it brings, what are the problems it solves and why is the
current code bad or wrong? Please explain all this in the commit
message, not just as an email reply.

In other words: if I'm bisecting a theoretical bug and then suddenly
conclude that this patch is the problem, how will I know what's going
to break once I revert this patch?

Thanks,
Paulo

> 
> Signed-off-by: Kumar, Mahesh <mahesh1.kumar at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index e4e6141..7258883 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5427,8 +5427,6 @@ static void haswell_crtc_enable(struct
> intel_crtc_state *pipe_config,
>  
>  	intel_color_set_csc(&pipe_config->base);
>  
> -	intel_crtc->active = true;
> -
>  	if (intel_crtc->config->has_pch_encoder)
>  		intel_set_cpu_fifo_underrun_reporting(dev_priv,
> pipe, false);
>  	else
> @@ -5475,6 +5473,8 @@ static void haswell_crtc_enable(struct
> intel_crtc_state *pipe_config,
>  	assert_vblank_disabled(crtc);
>  	drm_crtc_vblank_on(crtc);
>  
> +	intel_crtc->active = true;
> +
>  	intel_encoders_enable(crtc, pipe_config, old_state);
>  
>  	if (intel_crtc->config->has_pch_encoder) {