[Intel-gfx] [PATCH] drm/i915/phy: Quieten state loss across suspend

[Souza, Jose]

On Tue, 2020-11-17 at 17:14 +0000, Chris Wilson wrote:
> When the HW is powered down, the register state and links are lost. This
> may be an issue in the firmware, or in the code expectations; whatever
> it is, it is expected behaviour now for Tigerlake; stop warning!
> 
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/2411

We are missing a IFWI/firmware update to fix this issue, already asked CI team to update but no luck so far.

During icl_combo_phys_uninit() is expected to have the registers set with expected values as it was not powered down yet.

> Fixes: 239bef676d8e ("drm/i915/display: Implement new combo phy initialization step")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Clinton A Taylor <clinton.a.taylor at intel.com>
> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> Cc: Matt Roper <matthew.d.roper at intel.com>
> Cc: José Roberto de Souza <jose.souza at intel.com>
> Cc: <stable at vger.kernel.org> # v5.9+
> ---
>  drivers/gpu/drm/i915/display/intel_combo_phy.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_combo_phy.c b/drivers/gpu/drm/i915/display/intel_combo_phy.c
> index d5ad61e4083e..9a87df982af8 100644
> --- a/drivers/gpu/drm/i915/display/intel_combo_phy.c
> +++ b/drivers/gpu/drm/i915/display/intel_combo_phy.c
> @@ -428,9 +428,9 @@ static void icl_combo_phys_uninit(struct drm_i915_private *dev_priv)
>  
> 
> 
> 
>  		if (phy == PHY_A &&
>  		    !icl_combo_phy_verify_state(dev_priv, phy))
> -			drm_warn(&dev_priv->drm,
> -				 "Combo PHY %c HW state changed unexpectedly\n",
> -				 phy_name(phy));
> +			drm_dbg_kms(&dev_priv->drm,
> +				    "Combo PHY %c HW state changed unexpectedly\n",
> +				    phy_name(phy));
>  
> 
> 
> 
>  		if (!has_phy_misc(dev_priv, phy))
>  			goto skip_phy_misc;