[Intel-gfx] [PATCH 5/9] drm/i915: Clear out DPLL state from pipe config in DSI get config

[Daniel Vetter]

On Mon, Jun 29, 2015 at 03:25:52PM +0300, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> VLV/CHV don't use the DPLL with DSI, so just clear out the DPLL state
> from the pipe_config in intel_dsi_get_config(). This avoids spurious
> state checker warnings. We already did it this way for DPLL_MD, but do
> it for DPLL too.
> 
> Toss in a WARN to intel_dsi_pre_enable() to make sure the ref clocks
> are enabled however. Supposedly they have some meaning to DSI too.
> We now keep the ref clocks always enabled while the disp2d well is
> enabled.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dsi.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 36e2148..92bb252 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -421,18 +421,12 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder)
>  
>  	/* Disable DPOunit clock gating, can stall pipe
>  	 * and we need DPLL REFA always enabled */
> -	tmp = I915_READ(DPLL(pipe));
> -	tmp |= DPLL_REF_CLK_ENABLE_VLV;
> -	I915_WRITE(DPLL(pipe), tmp);
> -
> -	/* update the hw state for DPLL */
> -	intel_crtc->config->dpll_hw_state.dpll = DPLL_INTEGRATED_REF_CLK_VLV |
> -		DPLL_REF_CLK_ENABLE_VLV | DPLL_VGA_MODE_DIS;
> -
>  	tmp = I915_READ(DSPCLK_GATE_D);
>  	tmp |= DPOUNIT_CLOCK_GATE_DISABLE;
>  	I915_WRITE(DSPCLK_GATE_D, tmp);
>  
> +	WARN_ON((I915_READ(DPLL(pipe)) & DPLL_REF_CLK_ENABLE_VLV) == 0);
> +
>  	/* put device in ready state */
>  	intel_dsi_device_ready(encoder);
>  
> @@ -635,9 +629,10 @@ static void intel_dsi_get_config(struct intel_encoder *encoder,
>  	DRM_DEBUG_KMS("\n");
>  
>  	/*
> -	 * DPLL_MD is not used in case of DSI, reading will get some default value
> -	 * set dpll_md = 0
> +	 * DPLL is not used in case of DSI, reading will getsome default value.
> +	 * Clear the state to keep the state checker happy.
>  	 */
> +	pipe_config->dpll_hw_state.dpll = 0;
>  	pipe_config->dpll_hw_state.dpll_md = 0;

State configs are supposed to be kzallocated. Needing this indicates a
pretty serious bug - I'd vote to instead also ditch the dpll_md line and
fix the offender.
-Daniel

>  
>  	pclk = vlv_get_dsi_pclk(encoder, pipe_config->pipe_bpp);
> -- 
> 2.3.6
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch