Re: [PATCH] drm/i915: Restore global mappings upon resume

[Ben Widawsky <ben@bwidawsk.net>]

On Thu, Sep 26, 2013 at 09:22:45AM +0100, Chris Wilson wrote:
> commit c6916417c8575637659686ff0e4f744babf0cb4e
> Author: Ben Widawsky <ben@bwidawsk.net>
> Date:   Tue Sep 24 09:58:00 2013 -0700
> 
>     drm/i915: Use the new vm [un]bind functions
> 
> changes the interpretation of the bind routines, and in particular we
> only bind into the global GTT if we pass a flag to the routine. So upon
> resume, we need to ask for whatever we thing is bound into the global
> GTT (cursors, fences, scanouts) to be rebound or else glorious
> corruption ensues.
> 
> v2.1: Clear the is-bound flags before attempting to rebind.

Probably wouldn't hurt to add a comment on why you are clearing flags on
resume (which would seemingly want to be cleared on suspend, but for
pretty good reason cannot).

> 
> Fixes: i-g-t/gem_suspend
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69834
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ben Widawsky <ben@bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index e053f14..55a8d87 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -508,8 +508,14 @@ void i915_gem_restore_gtt_mappings(struct drm_device *dev)
>  	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
>  		struct i915_vma *vma = i915_gem_obj_to_vma(obj,
>  							   &dev_priv->gtt.base);
> +		unsigned flags = obj->has_global_gtt_mapping ? GLOBAL_BIND : 0;
> +
>  		i915_gem_clflush_object(obj, obj->pin_display);
> -		vma->vm->bind_vma(vma, obj->cache_level, 0);
> +
> +		obj->has_global_gtt_mapping = false;
> +		obj->has_aliasing_ppgtt_mapping = false;

Actually, the aliasing PPGTT mapping may very well still be in tact.
Unless I'm not seeing something that you are.

> +
> +		vma->vm->bind_vma(vma, obj->cache_level, flags);
>  	}
>  
>  	i915_gem_chipset_flush(dev);
> -- 
> 1.8.4.rc3
> 

-- 
Ben Widawsky, Intel Open Source Technology Center