[Intel-gfx] [PATCH] drm/i915/display: Increase AUX timeout for Type-C

[Murthy, Arun R]

> -----Original Message-----
> From: Kandpal, Suraj <suraj.kandpal at intel.com>
> Sent: Monday, April 3, 2023 1:32 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Murthy, Arun R <arun.r.murthy at intel.com>; Sharma, Swati2
> <swati2.sharma at intel.com>; Kandpal, Suraj <suraj.kandpal at intel.com>
> Subject: [PATCH] drm/i915/display: Increase AUX timeout for Type-C
> 
> Type-C PHYs are taking longer than expected for Aux IO Power Enabling.
> Workaround: Increase the timeout.
> 
> WA: 14017271110
> Bspec: 55480
> 
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
>  .../drm/i915/display/intel_display_power_well.c   | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power_well.c
> b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> index 62bafcbc7937..357617b9b725 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power_well.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power_well.c
> @@ -252,6 +252,7 @@ static void hsw_wait_for_power_well_enable(struct
> drm_i915_private *dev_priv,
>  					   bool timeout_expected)
>  {
>  	const struct i915_power_well_regs *regs = power_well->desc->ops-
> >regs;
> +	enum phy phy = icl_aux_pw_to_phy(dev_priv, power_well);
>  	int pw_idx = i915_power_well_instance(power_well)->hsw.idx;
> 
>  	/*
> @@ -264,6 +265,20 @@ static void hsw_wait_for_power_well_enable(struct
> drm_i915_private *dev_priv,
>  		return;
>  	}
> 
> +	/*
> +	 * WA: 14017271110
> +	 * Type-C Phy are taking longer than expected for AUX IO Power
> Enabling.
> +	 * Increase timeout to 500ms.
> +	 */
> +	if (IS_ALDERLAKE_P(dev_priv) && intel_phy_is_tc(dev_priv, phy)) {
> +		if (intel_de_wait_for_set(dev_priv, regs->driver,
> +
> HSW_PWR_WELL_CTL_STATE(pw_idx), 500)) {
> +			drm_dbg_kms(&dev_priv->drm, "%s power well
> enable timeout\n",
> +				    intel_power_well_name(power_well));
> +			return;
> +		}
> +	}

After execution of this on success it will again execute the wait_for() for HSW_PWR_WELL_CTL_STATE.
Instead can a variable 'delay' be added that can be passed to intel_de_wait_for_set() and this variable 'delay' can be initialized with corresponding value.

Thanks and Regards,
Arun R Murthy
-------------------
> +
>  	/* Timeout for PW1:10 us, AUX:not specified, other PWs:20 us. */
>  	if (intel_de_wait_for_set(dev_priv, regs->driver,
>  				  HSW_PWR_WELL_CTL_STATE(pw_idx), 1)) {
> --
> 2.25.1