[Intel-gfx] [PATCH 2/3] drm/i915: Do not touch PCH handshake registers if PCH is not present

[Ville Syrjälä]

On Tue, Nov 20, 2018 at 02:32:41PM -0800, José Roberto de Souza wrote:
> If no PCH was detected in intel_detect_pch() don't touch the
> handshake registers.

We are explicitly told to frob this on BXT/GLK. So this doesn't make
sense. What is this supposed to fix?

> 
> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 1c2de9b69a19..f33f335d6106 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -3325,6 +3325,9 @@ static void intel_pch_reset_handshake(struct drm_i915_private *dev_priv,
>  	i915_reg_t reg;
>  	u32 reset_bits, val;
>  
> +	if (!HAS_PCH_SPLIT(dev_priv))
> +		return;
> +
>  	if (IS_IVYBRIDGE(dev_priv)) {
>  		reg = GEN7_MSG_CTL;
>  		reset_bits = WAIT_FOR_PCH_FLR_ACK | WAIT_FOR_PCH_RESET_ACK;
> -- 
> 2.19.1
> 
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-- 
Ville Syrjälä
Intel