[Intel-gfx] [PATCH 2/4] drm/i915/fbc: Fix nuke for pre-snb platforms

[Souza, Jose]

On Thu, 2020-07-02 at 18:37 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The MSG_FBC_REND_STATE register only exists on snb+. For older
> platforms (would also work for snb+) we can simply rewite DSPSURF
> to trigger a flip nuke.
> 
> While generally RMW is considered harmful we'll use it here for
> simplicity. And since FBC doesn't exist in i830 we don't have to
> worry about the DSPSURF double buffering hardware fails present
> on that platform.

Did not found a explicit statement about writing DSPSURF will nuke compressed buffer but that makes sense, also checked that MSG_FBC_REND_STATE do not
exist this older platforms.

Reviewed-by: José Roberto de Souza <jose.souza at intel.com>

> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 34 +++++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> index d30c2a389294..036546ce8db8 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -187,8 +187,30 @@ static bool g4x_fbc_is_active(struct drm_i915_private *dev_priv)
>  	return intel_de_read(dev_priv, DPFC_CONTROL) & DPFC_CTL_EN;
>  }
>  
> +static void i8xx_fbc_recompress(struct drm_i915_private *dev_priv)
> +{
> +	struct intel_fbc_reg_params *params = &dev_priv->fbc.params;
> +	enum i9xx_plane_id i9xx_plane = params->crtc.i9xx_plane;
> +
> +	spin_lock_irq(&dev_priv->uncore.lock);
> +	intel_de_write_fw(dev_priv, DSPADDR(i9xx_plane),
> +			  intel_de_read_fw(dev_priv, DSPADDR(i9xx_plane)));
> +	spin_unlock_irq(&dev_priv->uncore.lock);
> +}
> +
> +static void i965_fbc_recompress(struct drm_i915_private *dev_priv)
> +{
> +	struct intel_fbc_reg_params *params = &dev_priv->fbc.params;
> +	enum i9xx_plane_id i9xx_plane = params->crtc.i9xx_plane;
> +
> +	spin_lock_irq(&dev_priv->uncore.lock);
> +	intel_de_write_fw(dev_priv, DSPSURF(i9xx_plane),
> +			  intel_de_read_fw(dev_priv, DSPSURF(i9xx_plane)));
> +	spin_unlock_irq(&dev_priv->uncore.lock);
> +}
> +
>  /* This function forces a CFB recompression through the nuke operation. */
> -static void intel_fbc_recompress(struct drm_i915_private *dev_priv)
> +static void snb_fbc_recompress(struct drm_i915_private *dev_priv)
>  {
>  	struct intel_fbc *fbc = &dev_priv->fbc;
>  
> @@ -198,6 +220,16 @@ static void intel_fbc_recompress(struct drm_i915_private *dev_priv)
>  	intel_de_posting_read(dev_priv, MSG_FBC_REND_STATE);
>  }
>  
> +static void intel_fbc_recompress(struct drm_i915_private *dev_priv)
> +{
> +	if (INTEL_GEN(dev_priv) >= 6)
> +		snb_fbc_recompress(dev_priv);
> +	else if (INTEL_GEN(dev_priv) >= 4)
> +		i965_fbc_recompress(dev_priv);
> +	else
> +		i8xx_fbc_recompress(dev_priv);
> +}
> +
>  static void ilk_fbc_activate(struct drm_i915_private *dev_priv)
>  {
>  	struct intel_fbc_reg_params *params = &dev_priv->fbc.params;