From: Chris Wilson <chris@chris-wilson.co.uk>
To: Jason Ekstrand <jason@jlekstrand.net>,
dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org
Cc: Dave Airlie <airlied@redhat.com>,
Jason Ekstrand <jason@jlekstrand.net>,
Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH] RFC: i915: Drop relocation support on Gen12+
Date: Thu, 07 May 2020 16:44:27 +0100 [thread overview]
Message-ID: <158886626795.20858.1870213936656066157@build.alporthouse.com> (raw)
In-Reply-To: <20200507153600.314454-1-jason@jlekstrand.net>
Quoting Jason Ekstrand (2020-05-07 16:36:00)
> The Vulkan driver in Mesa for Intel hardware never uses relocations if
> it's running on a version of i915 that supports at least softpin which
> all versions of i915 supporting Gen12 do. On the OpenGL side, Gen12 is
> only supported by iris which never uses relocations. The older i965
> driver in Mesa does use relocations but it only supports Intel hardware
> through Gen11 and has been deprecated for all hardware Gen9+. The entire
> relocation UAPI and related infrastructure, therefore, doesn't have any
> open-source userspace consumer starting with Gen12.
>
> Rejecting relocations starting with Gen12 has the benefit that we don't
> have to bother supporting it on platforms with local memory. Given how
> much CPU touching of memory is required for relocations, not having to
> do so on platforms where not all memory is directly CPU-accessible
> carries significant advantages.
You are not supplying them, the kernel is not checking them [as they
don't exist], so there is no material benefit. The only question is
maintainability.
How confident are you that you will never use them and rewrite the
media-driver? The code exists, will be tested, and can just as easily
expire with the rest of execbuffer2.
-Chris
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next prev parent reply other threads:[~2020-05-07 15:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 15:36 [PATCH] RFC: i915: Drop relocation support on Gen12+ Jason Ekstrand
2020-05-07 15:44 ` Chris Wilson [this message]
2020-05-07 16:00 ` Jason Ekstrand
2020-05-07 18:27 ` Dave Airlie
2020-05-08 5:58 ` Joonas Lahtinen
2020-06-25 17:22 ` Dave Airlie
2021-03-10 21:26 ` [PATCH] i915: Drop relocation support on all new hardware Jason Ekstrand
2021-03-10 21:50 ` [PATCH] i915: Drop relocation support on all new hardware (v3) Jason Ekstrand
2021-03-10 22:56 ` Jason Ekstrand
2021-03-11 8:14 ` [Intel-gfx] " Lucas De Marchi
2021-03-11 10:20 ` Matthew Auld
2021-03-11 9:54 ` Tvrtko Ursulin
2021-03-11 11:44 ` Zbigniew Kempczyński
2021-03-11 15:50 ` Jason Ekstrand
2021-03-11 15:57 ` Daniel Vetter
2021-03-11 16:24 ` Jason Ekstrand
2021-03-11 16:50 ` Zbigniew Kempczyński
2021-03-11 17:18 ` Jason Ekstrand
2021-03-11 18:19 ` Zbigniew Kempczyński
2021-03-11 18:57 ` Jason Ekstrand
2021-03-12 14:16 ` Daniel Vetter
2021-03-11 16:31 ` Chris Wilson
2021-03-11 16:40 ` Jason Ekstrand
2021-03-11 16:26 ` [PATCH] drm/i915/gem: Drop relocation support on all new hardware (v4) Jason Ekstrand
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