[Intel-gfx] [PATCH] drm/i915: disable LVDS clock gating on CPT

[Jani Nikula]

On Tue, 01 Oct 2013, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> Needed to prevent display corruption in high res panels.

Clueless question, could we do this only when we have a high res panel
connected? More trouble than it's worth?

BR,
Jani.


>
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/i915_reg.h |    2 ++
>  drivers/gpu/drm/i915/intel_pm.c |    4 +++-
>  2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 96fd2ce..cca670a 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4338,7 +4338,9 @@
>  #define FDI_RX_CHICKEN(pipe) _PIPE(pipe, _FDI_RXA_CHICKEN, _FDI_RXB_CHICKEN)
>  
>  #define SOUTH_DSPCLK_GATE_D	0xc2020
> +#define  PCH_LVDSUNIT_CLOCK_GATE_DISABLE (1<<30)
>  #define  PCH_DPLSUNIT_CLOCK_GATE_DISABLE (1<<29)
> +#define  PCH_LVDSUNIT2_CLOCK_GATE_DISABLE (1<<14)
>  #define  PCH_LP_PARTITION_LEVEL_DISABLE  (1<<12)
>  
>  /* CPU: FDI_TX */
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 698257c..f6765e0 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4791,7 +4791,9 @@ static void cpt_init_clock_gating(struct drm_device *dev)
>  	 * gating for the panel power sequencer or it will fail to
>  	 * start up when no ports are active.
>  	 */
> -	I915_WRITE(SOUTH_DSPCLK_GATE_D, PCH_DPLSUNIT_CLOCK_GATE_DISABLE);
> +	I915_WRITE(SOUTH_DSPCLK_GATE_D, PCH_DPLSUNIT_CLOCK_GATE_DISABLE |
> +		   PCH_LVDSUNIT_CLOCK_GATE_DISABLE |
> +		   PCH_LVDSUNIT2_CLOCK_GATE_DISABLE);
>  	I915_WRITE(SOUTH_CHICKEN2, I915_READ(SOUTH_CHICKEN2) |
>  		   DPLS_EDP_PPS_FIX_DIS);
>  	/* The below fixes the weird display corruption, a few pixels shifted
> -- 
> 1.7.9.5
>
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-- 
Jani Nikula, Intel Open Source Technology Center