From: Daniel Vetter <daniel@ffwll.ch>
To: Ben Widawsky <ben@bwidawsk.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] drm/i915: swizzling support for snb/ivb
Date: Mon, 6 Feb 2012 17:06:04 +0100 [thread overview]
Message-ID: <20120206160604.GC4066@phenom.ffwll.local> (raw)
In-Reply-To: <4F2DF3E5.80309@bwidawsk.net>
On Sat, Feb 04, 2012 at 07:13:41PM -0800, Ben Widawsky wrote:
> On 02/02/12 00:40, Daniel Vetter wrote:
> >On Wed, Feb 01, 2012 at 09:30:57PM -0800, Ben Widawsky wrote:
> >[...]
> >>I'd also say it's not a bad idea to elaborate the assumption that we
> >>never have less than 256MB of memory WARN_ON(dimm_c0 + dimm_c1 == 0).
> >
> >I'm pretty sure that we can't boot with 0mb of ram ;-) The other thing is
> >that swizzling is a pure preformance optimization - if we enable it on
> >setup where it's not required we'll only annoy the memory controller with
> >less efficient access patterns.
>
> What I meant was, this value is still 0 in say, a system with 2
> 128MB DIMMs.
Well, I have a feeling that 256mb is the smallest size for a ddr3 dimm.
But I'm a bit too lazy to check that (and frankly wouldn't know where).
Furthermore swizzling on gen6+ is afaics just a performance thing and
should never affect correctness, so even if 128mb dimms exist I think we
can just not care - performance isn't gonna be stellar anyway ;-)
-Daniel
--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48
next prev parent reply other threads:[~2012-02-06 16:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-31 15:47 [PATCH 1/3] drm/i915: swizzling support for snb/ivb Daniel Vetter
2012-01-31 15:47 ` [PATCH 2/3] drm/i915: consolidate swizzling control bit frobbing Daniel Vetter
2012-02-01 21:37 ` Ben Widawsky
2012-02-01 22:23 ` Daniel Vetter
2012-02-08 22:17 ` Ben Widawsky
2012-02-08 22:19 ` Daniel Vetter
2012-01-31 15:47 ` [PATCH 3/3] drm/i915: add gen6+ registers to i915_swizzle_info Daniel Vetter
2012-02-01 21:39 ` Ben Widawsky
2012-02-08 22:20 ` Daniel Vetter
2012-02-01 21:35 ` [PATCH 1/3] drm/i915: swizzling support for snb/ivb Ben Widawsky
2012-02-01 22:16 ` Daniel Vetter
2012-02-01 22:26 ` Chris Wilson
2012-02-01 23:15 ` [PATCH] " Daniel Vetter
2012-02-02 5:30 ` Ben Widawsky
2012-02-02 8:40 ` Daniel Vetter
2012-02-05 3:13 ` Ben Widawsky
2012-02-06 16:06 ` Daniel Vetter [this message]
2012-02-02 8:58 ` Daniel Vetter
2012-02-04 20:59 ` Eric Anholt
2012-02-06 15:45 ` Daniel Vetter
2012-02-07 19:56 ` Eric Anholt
2012-02-08 22:17 ` Daniel Vetter
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