Re: [PATCH] drm/i915: vlv_prepare_pll is only needed in case of non DSI interfaces

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Shobhit Kumar <shobhit.kumar@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>,
	Daniel Vetter <daniel.vetter@intel.com>,
	intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] drm/i915: vlv_prepare_pll is only needed in case of non DSI interfaces
Date: Tue, 24 Jun 2014 16:45:50 +0300	[thread overview]
Message-ID: <20140624134550.GX27580@intel.com> (raw)
In-Reply-To: <1403616099-12007-1-git-send-email-shobhit.kumar@intel.com>

On Tue, Jun 24, 2014 at 06:51:39PM +0530, Shobhit Kumar wrote:
> For MIPI, DSI PLL is configured separately in vlv_configure_dsi_pll
> during the DSI enable sequence
> 
> Causing WARN dump otherwise in dpio_reads
> 
> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>

Yeah, the DPIO power wells might be down when enabling a DSI display so
we shouldn't go poking at DPIO registers.

But please add a !IS_CHERRYVIEW check there also, and then you can add:
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Looks like I need to split up chv_update_pll() in a similar fasion.

> ---
>  drivers/gpu/drm/i915/intel_display.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index fa77557..2fa7152 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4629,7 +4629,10 @@ static void valleyview_crtc_enable(struct drm_crtc *crtc)
>  	if (intel_crtc->active)
>  		return;
>  
> -	vlv_prepare_pll(intel_crtc);
> +	is_dsi = intel_pipe_has_type(crtc, INTEL_OUTPUT_DSI);
> +
> +	if (!is_dsi)
> +		vlv_prepare_pll(intel_crtc);
>  
>  	/* Set up the display plane register */
>  	dspcntr = DISPPLANE_GAMMA_ENABLE;
> @@ -4663,8 +4666,6 @@ static void valleyview_crtc_enable(struct drm_crtc *crtc)
>  		if (encoder->pre_pll_enable)
>  			encoder->pre_pll_enable(encoder);
>  
> -	is_dsi = intel_pipe_has_type(crtc, INTEL_OUTPUT_DSI);
> -
>  	if (!is_dsi) {
>  		if (IS_CHERRYVIEW(dev))
>  			chv_enable_pll(intel_crtc);
> -- 
> 1.9.1
> 
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-- 
Ville Syrjälä
Intel OTC