[Intel-gfx] [PATCH 04/18] drm/i915: don't call Haswell PCH code when we can't or don't need

[Jani Nikula]

On Tue, 23 Oct 2012, Paulo Zanoni <przanoni at gmail.com> wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>
> On Ironlake we have one PCH transcoder and FDI per pipe, so we know
> that if ironlake_crtc_driving_pch returns false we can disable the PCH
> transcoder and we also know that when we disable the crtc we can also
> disable the PCH transcoder.
>
> On Haswell there is only 1 PCH transcoder and FDI and they can be used
> by any CRTC. So if for one specific crtc haswell_crtc_driving_pch
> returns false we can't assert anything about the state of the PCH
> transcoder or the FDI link without checking if any other CRTC is using
> the PCH.
>
> So on this commit remove the "assert_fdi_{t,r}x_disabled" form
> haswell_crtc_enable and also only disable FDI and the PCH transcoder
> if the port being disabled was actually a PCH port (we only have one
> port using PCH: the VGA port).

I first wrote a message saying this is wrong, then revisited the patch,
and finally reached the same conclusions as you...

Reviewed-by: Jani Nikula <jani.nikula at intel.com>


>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 0c4e9c5..67c9472 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3286,12 +3286,8 @@ static void haswell_crtc_enable(struct drm_crtc *crtc)
>  
>  	is_pch_port = haswell_crtc_driving_pch(crtc);
>  
> -	if (is_pch_port) {
> +	if (is_pch_port)
>  		ironlake_fdi_pll_enable(intel_crtc);
> -	} else {
> -		assert_fdi_tx_disabled(dev_priv, pipe);
> -		assert_fdi_rx_disabled(dev_priv, pipe);
> -	}
>  
>  	for_each_encoder_on_crtc(dev, crtc, encoder)
>  		if (encoder->pre_enable)
> @@ -3433,10 +3429,13 @@ static void haswell_crtc_disable(struct drm_crtc *crtc)
>  	struct intel_encoder *encoder;
>  	int pipe = intel_crtc->pipe;
>  	int plane = intel_crtc->plane;
> +	bool is_pch_port;
>  
>  	if (!intel_crtc->active)
>  		return;
>  
> +	is_pch_port = haswell_crtc_driving_pch(crtc);
> +
>  	for_each_encoder_on_crtc(dev, crtc, encoder)
>  		encoder->disable(encoder);
>  
> @@ -3463,14 +3462,12 @@ static void haswell_crtc_disable(struct drm_crtc *crtc)
>  		if (encoder->post_disable)
>  			encoder->post_disable(encoder);
>  
> -	ironlake_fdi_disable(crtc);
> -
> -	intel_disable_transcoder(dev_priv, pipe);
> -
> -	/* disable PCH DPLL */
> -	intel_disable_pch_pll(intel_crtc);
> -
> -	ironlake_fdi_pll_disable(intel_crtc);
> +	if (is_pch_port) {
> +		ironlake_fdi_disable(crtc);
> +		intel_disable_transcoder(dev_priv, pipe);
> +		intel_disable_pch_pll(intel_crtc);
> +		ironlake_fdi_pll_disable(intel_crtc);
> +	}
>  
>  	intel_crtc->active = false;
>  	intel_update_watermarks(dev);
> -- 
> 1.7.11.4
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx