[Intel-gfx] [PATCH 03/12] drm/i915/ibx: ensure the HW is powered during PLL HW readout

[Mika Kuoppala]

Imre Deak <imre.deak at intel.com> writes:

> The assumption when adding the intel_display_power_is_enabled() checks
> was that if it returns success the power can't be turned off afterwards
> during the HW access, which is guaranteed by modeset locks. This isn't
> always true, so make sure we hold a dedicated reference for the time of
> the access.
>
> Signed-off-by: Imre Deak <imre.deak at intel.com>

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>

> ---
>  drivers/gpu/drm/i915/intel_display.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 6abfc54..fe249ff 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -13699,7 +13699,7 @@ static bool ibx_pch_dpll_get_hw_state(struct drm_i915_private *dev_priv,
>  {
>  	uint32_t val;
>  
> -	if (!intel_display_power_is_enabled(dev_priv, POWER_DOMAIN_PLLS))
> +	if (!intel_display_power_get_if_enabled(dev_priv, POWER_DOMAIN_PLLS))
>  		return false;
>  
>  	val = I915_READ(PCH_DPLL(pll->id));
> @@ -13707,6 +13707,8 @@ static bool ibx_pch_dpll_get_hw_state(struct drm_i915_private *dev_priv,
>  	hw_state->fp0 = I915_READ(PCH_FP0(pll->id));
>  	hw_state->fp1 = I915_READ(PCH_FP1(pll->id));
>  
> +	intel_display_power_put(dev_priv, POWER_DOMAIN_PLLS);
> +
>  	return val & DPLL_VCO_ENABLE;
>  }
>  
> -- 
> 2.5.0
>
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