[Intel-gfx] [PATCH] drm/i915: FBC off for ironlake, otherwise on by default

[Magnus Kessler]

On Monday 19 Sep 2011 21:36:36 Keith Packard wrote:
> Make the default FBC behaviour chipset specific, allowing us to turn
> it on by default for everything except Ironlake where it has been
> seen to cause trouble with screen updates.
> 
> Signed-off-by: Keith Packard <keithp at keithp.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c      |    4 ++--
>  drivers/gpu/drm/i915/intel_display.c |   10 +++++++++-
>  2 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c
> b/drivers/gpu/drm/i915/i915_drv.c index ce045a8..f07e425 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -67,11 +67,11 @@ module_param_named(i915_enable_rc6, i915_enable_rc6,
> int, 0600); MODULE_PARM_DESC(i915_enable_rc6,
>  		"Enable power-saving render C-state 6 (default: true)");
> 
> -unsigned int i915_enable_fbc __read_mostly = 1;
> +unsigned int i915_enable_fbc __read_mostly = -1;
>  module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
>  MODULE_PARM_DESC(i915_enable_fbc,
>  		"Enable frame buffer compression for power savings "
> -		"(default: false)");
> +		"(default: -1 (use per-chip default))");
> 
>  unsigned int i915_lvds_downclock __read_mostly = 0;
>  module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c index 9fb4a40..bc05deb 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -1799,6 +1799,7 @@ static void intel_update_fbc(struct drm_device *dev)
>  	struct drm_framebuffer *fb;
>  	struct intel_framebuffer *intel_fb;
>  	struct drm_i915_gem_object *obj;
> +	int enable_fbc;
> 
>  	DRM_DEBUG_KMS("\n");
> 
> @@ -1839,7 +1840,14 @@ static void intel_update_fbc(struct drm_device *dev)
>  	intel_fb = to_intel_framebuffer(fb);
>  	obj = intel_fb->obj;
> 
> -	if (!i915_enable_fbc) {
> +	enable_fbc = i915_enable_fbc;
> +	if (enable_fbc < 0) {
> +		DRM_DEBUG_KMS("fbc set to per-chip default\n");
> +		enable_fbc = 1;
> +		if (INTEL_INFO(dev)->gen == 5)
> +			enable_fbc = 0;
> +	}
> +	if (!enable_fbc) {
>  		DRM_DEBUG_KMS("fbc disabled per module param (default off)\n");

As the default is no longer "off" on all chipset, shouldn't this debug message 
be changed to simply read "fbc disabled per module param\n"?

>  		dev_priv->no_fbc_reason = FBC_MODULE_PARAM;
>  		goto out_disable;