[Intel-gfx] [PATCH] drm/i915/display: check if compressed_llb was allocated

[Souza, Jose]

On Thu, 2021-07-01 at 10:03 +0100, Matthew Auld wrote:
> If we hit the error path here we unconditionally call
> i915_gem_stolen_remove_node, even though we only allocate the
> compressed_llb on older platforms. Therefore we should first check that
> we actually allocated the node before trying to remove it.

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

> 
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/3709
> Fixes: 46b2c40e0af3 ("drm/i915/fbc: Allocate llb before cfb")
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> index 7dc72e4a4656..82effb64a3b9 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -516,7 +516,8 @@ static int intel_fbc_alloc_cfb(struct drm_i915_private *dev_priv,
>  	return 0;
>  
>  err_llb:
> -	i915_gem_stolen_remove_node(dev_priv, &fbc->compressed_llb);
> +	if (drm_mm_node_allocated(&fbc->compressed_llb))
> +		i915_gem_stolen_remove_node(dev_priv, &fbc->compressed_llb);
>  err:
>  	if (drm_mm_initialized(&dev_priv->mm.stolen))
>  		drm_info_once(&dev_priv->drm, "not enough stolen space for compressed buffer (need %d more bytes), disabling. Hint: you may be able to increase stolen memory size in the BIOS to avoid this.\n", size);