From: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: fix relaxed tiling on gen2
Date: Sat, 26 Mar 2011 18:23:39 +0000 [thread overview]
Message-ID: <1bdc18$k0pvil@fmsmga002.fm.intel.com> (raw)
In-Reply-To: <1301149377-7195-1-git-send-email-daniel.vetter@ffwll.ch>
On Sat, 26 Mar 2011 15:22:57 +0100, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> A tile on gen2 has a size of 2kb, stride of 128 bytes and 16 rows.
You know thats what it says in the gen2 docs as well under FENCE. :(
> Userspace was broken and assumed 8 rows. Complain with a printk_once
> and disallow such tiling requests.
However, we know that userspace only requests correctly aligned regions by
accident due to the rounding up to the next bucket size in libdrm.
> Also experiments and randoms cues from i81x docs suggest that y-tiling
> doesn't work with fences (it's already known to be broken on the blitter).
> Original idea seems to be to use y-tiling for textures with a manually
> tiling upload path. Hence also disallow y-tiling - current userspace
> doesn't use it at all, anyway.
gen2 docs say that the FENCE upload via the CPU can handle Y-tiling on
all chipsets but 855GM. Go figure. (To handle Y-tiling uploads on 855GM it
says to BLT from X to Y...)
In which case it is only an error in i915_gem_fault() for 855GM &
Y-tiling.
So whilst I think we've found the right bug, I don't quite think we've got
the right patch yet.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
next prev parent reply other threads:[~2011-03-26 18:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-25 9:36 [PATCH] drm/i915: Round-up GTT allocations for unfenced surfaces to the next tile row Chris Wilson
2011-03-25 12:16 ` Chris Wilson
2011-03-26 8:52 ` Chris Wilson
2011-03-26 9:20 ` Daniel Vetter
2011-03-26 9:43 ` Chris Wilson
2011-03-26 14:22 ` [PATCH] drm/i915: fix relaxed tiling on gen2 Daniel Vetter
2011-03-26 18:23 ` Chris Wilson [this message]
2011-03-26 19:55 ` [PATCH] drm/i915: fix relaxed tiling on gen2 v2 Daniel Vetter
2011-03-26 20:44 ` Chris Wilson
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