[Intel-gfx] [PATCH 3/3] drm/i915: don't rewrite the GTT on resume

[Daniel Vetter]

On Sun, Oct 14, 2012 at 07:10:38PM -0700, Jesse Barnes wrote:
> The BIOS shouldn't be touching this memory across suspend/resume, so
> just leave it alone.  This saves us ~50ms on resume on my T420.

Is that 50ms still accurate with wc gtt ptes?
-Daniel

> 
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/i915_drv.c |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 824e3c8..95e2b8b 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -119,6 +119,10 @@ module_param_named(i915_enable_ppgtt, i915_enable_ppgtt, int, 0600);
>  MODULE_PARM_DESC(i915_enable_ppgtt,
>  		"Enable PPGTT (default: true)");
>  
> +int i915_needs_gtt_restore __read_mostly = 0;
> +module_param_named(gtt_restore, i915_needs_gtt_restore, int, 0600);
> +MODULE_PARM_DESC(gtt_restore, "Rewrite GTT on resume (default: false)");
> +
>  static struct drm_driver driver;
>  extern int intel_agp_enabled;
>  
> @@ -537,7 +541,8 @@ static int i915_drm_thaw(struct drm_device *dev)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	int error = 0;
>  
> -	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> +	if (drm_core_check_feature(dev, DRIVER_MODESET) &&
> +	    i915_needs_gtt_restore) {
>  		mutex_lock(&dev->struct_mutex);
>  		i915_gem_restore_gtt_mappings(dev);
>  		mutex_unlock(&dev->struct_mutex);
> -- 
> 1.7.9.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch