[Intel-gfx] [PATCH 3/3] drm/i915: don't rewrite the GTT on resume v2

[Daniel Vetter]

On Fri, Oct 26, 2012 at 10:08:38AM -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.
> 
> v2: change gtt restore default on pre-gen4 (Chris)
>     move needs_gtt_restore flag into dev_priv
> 
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>

I've just realized: GGTT PTEs are stored in stolen mem, and hence not
restored accross S4.
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_dma.c |    4 ++++
>  drivers/gpu/drm/i915/i915_drv.c |    3 ++-
>  drivers/gpu/drm/i915/i915_drv.h |    2 ++
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index b5977b4..c027266 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1339,6 +1339,10 @@ static int i915_load_modeset_init(struct drm_device *dev)
>  	/* FIXME: do pre/post-mode set stuff in core KMS code */
>  	dev->vblank_disable_allowed = 1;
>  
> +	/* Gen4+ should have saner BIOSes (we hope) */
> +	if (INTEL_INFO(dev)->gen < 4)
> +		dev_priv->needs_gtt_restore = true;
> +
>  	ret = intel_fbdev_init(dev);
>  	if (ret)
>  		goto cleanup_irq;
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 4d858a9..be9f47d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -540,7 +540,8 @@ static int i915_drm_thaw(struct drm_device *dev)
>  
>  	intel_gt_reset(dev);
>  
> -	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> +	if (drm_core_check_feature(dev, DRIVER_MODESET) &&
> +	    dev_priv->needs_gtt_restore) {
>  		mutex_lock(&dev->struct_mutex);
>  		i915_gem_restore_gtt_mappings(dev);
>  		mutex_unlock(&dev->struct_mutex);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1e84a59..a38eba8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -873,6 +873,8 @@ typedef struct drm_i915_private {
>  
>  	struct delayed_work gen6_power_work;
>  
> +	bool needs_gtt_restore;
> +
>  	enum no_fbc_reason no_fbc_reason;
>  
>  	struct drm_mm_node *compressed_fb;
> -- 
> 1.7.9.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch