From: "Dixit, Ashutosh" <ashutosh.dixit@intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: igt-dev@lists.freedesktop.org
Subject: Re: [igt-dev] [PATCH i-g-t 2/2] i915/treewide: Replace gem_mmap__gtt() by gem_mmap__device_coherent()
Date: Sat, 11 Jan 2020 18:57:22 -0800 [thread overview]
Message-ID: <875zhhtm99.wl-ashutosh.dixit@intel.com> (raw)
In-Reply-To: <157873229910.10140.6691170131873194678@skylake-alporthouse-com>
On Sat, 11 Jan 2020 00:44:59 -0800, Chris Wilson wrote:
>
> Here, we want OFFSET_WC etc added. So leave this style for a later patch,
> and focus on just converting the ones where we want any old mapping to
> device_coherent(). Another patch can focus on converting any __cpu maps
> that are only used for writes to device_coherent.
Thanks for the feedback Chris, makes sense, will rework and repost.
Some time ago, Dixit, Ashutosh wrote:
> On Sat, 11 Jan 2020 00:40:32 -0800, Chris Wilson wrote:
> > Quoting Ashutosh Dixit (2020-01-11 05:36:52)
> > > In order to preserve legacy behavior for devices with a mappable
> > > aperture try a GTT mapping first. Use a WC mapping only for devices
> > > without a mappable aperture.
> >
> > No...? It's just historical legacy from before we even had WC available.
> > Since we've had WC for basic mmappings, we prefer WC since it is not as
> > scarce and as precious a resource. (Not that it matters for most tests
> > since GTT thrashing in basic igt is unheard of!)
About this, I was assuming if we were using WC instead of GTT on legacy
(Gen < 6), we would have to set read/write domains to WC too, unless you
are saying it's not required? (From what I know, for later Gen's, setting
the domain to either GTT or WC is identical).
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next prev parent reply other threads:[~2020-01-12 2:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-11 5:36 [igt-dev] [PATCH i-g-t 1/2] lib/i915/gem_mman: Prioritize GTT mappings over WC Ashutosh Dixit
2020-01-11 5:36 ` [igt-dev] [PATCH i-g-t 2/2] i915/treewide: Replace gem_mmap__gtt() by gem_mmap__device_coherent() Ashutosh Dixit
2020-01-11 8:44 ` Chris Wilson
2020-01-12 2:57 ` Dixit, Ashutosh [this message]
2020-01-12 10:06 ` Chris Wilson
2020-01-15 16:27 ` Imre Deak
2020-01-15 17:03 ` Dixit, Ashutosh
2020-01-11 6:15 ` [igt-dev] ✓ Fi.CI.BAT: success for series starting with [i-g-t,1/2] lib/i915/gem_mman: Prioritize GTT mappings over WC Patchwork
2020-01-11 8:40 ` [igt-dev] [PATCH i-g-t 1/2] " Chris Wilson
2020-01-14 22:36 ` [igt-dev] ✗ Fi.CI.IGT: failure for series starting with [i-g-t,1/2] " Patchwork
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