[Intel-gfx] [PATCH 2/2] drm/i915: unreference default context on module unload

[Ben Widawsky]

On Tue, Apr 30, 2013 at 01:30:34PM +0300, Mika Kuoppala wrote:
> Before module unload is called, gpu_idle() will switch
> to default context. This will increment ref count of base
> object as the default context is 'running' on module unload
> time. Unreference the drm object so that when context
> is freed, base object is freed as well.
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>


I would have liked the patch to be distinct from the context refcounting
since it really is a fix unrelated to the context refcounting. I don't
think you need to resend though.

I also think the commit message is false. The unload code will call
gpu_idle, yes, but it also will also idle the ring, wait for it to
complete and then immediately call i915_gem_retire_requests. Unless I'm
missing something that will handle the missing unref, and the only ref
possibly at that point is the one we have from when we created the
object.

The reset case can leave a ref over - but that's okay AFAICT.

I know we discussed this on IRC a few days ago, and then you convinced
me that we need this, but my brain reset. Can you explain where I've
gotten lost?

I still want to play around with patch 1 a bit more.

> ---
>  drivers/gpu/drm/i915/i915_gem_context.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index 9e8c685..30f7f4c 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -274,6 +274,7 @@ void i915_gem_context_fini(struct drm_device *dev)
>  	intel_gpu_reset(dev);
>  
>  	i915_gem_object_unpin(dctx->obj);
> +	drm_gem_object_unreference(&dctx->obj->base);
>  	i915_gem_context_unreference(dctx);
>  }
>  
> -- 
> 1.7.9.5
> 
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-- 
Ben Widawsky, Intel Open Source Technology Center