Re: [PATCH 09/17] drm/i915: init ring->id early

[Ben Widawsky <ben@bwidawsk.net>]

On Sun, Dec 15, 2013 at 09:24:11AM +0000, Chris Wilson wrote:
> On Sat, Dec 14, 2013 at 05:42:42PM -0800, Ben Widawsky wrote:
> > On Sat, Dec 14, 2013 at 09:45:34PM +0000, Chris Wilson wrote:
> > > On Fri, Dec 13, 2013 at 08:15:57PM -0800, Ben Widawsky wrote:
> > > > Having the ring id all set up will allow us to use some macro shortcuts
> > > > during ringbuffer init. Admittedly it leaves the code a bit confusing,
> > > > having the initialization of the id member in a separate place - but I
> > > > think the savings is worth it.
> > > 
> > > This is not required since the macro could be written more simply as
> > > ring[i]->id == i.
> > > -Chris
> > > 
> > 
> > It could be written as ring->id = i. Is that what you mean? I didn't
> > quite follow the "not required" part.
> 
> Afaict this pre-init is only required because the macro you wrote
> depends upon ring[n]->id, but the macro can be trivially written not to
> use ring[n]->id but n.
> -Chris
> 

It appears so. I know for certain something blew up with an earlier
version of this patch, but the original version was indeed not the same.
I do need ring->id for the macro, but that's not a problem here.

So yeah, look like good advice, and I feel silly.

-- 
Ben Widawsky, Intel Open Source Technology Center