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From: Thomas Hellstrom <thellstrom@vmware.com>
To: Chris Wilson <chris@chris-wilson.co.uk>,
	airlied@gmail.com, airlied@redhat.com,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/gem: Warn on illegal use of the dumb buffer interface v2
Date: Fri, 21 Nov 2014 15:48:33 +0100	[thread overview]
Message-ID: <546F50C1.6070803@vmware.com> (raw)
In-Reply-To: <20141121141419.GU20532@nuc-i3427.alporthouse.com>

On 11/21/2014 03:14 PM, Chris Wilson wrote:
> On Thu, Nov 20, 2014 at 09:56:25AM +0100, Thomas Hellstrom wrote:
>> It happens on occasion that developers of generic user-space applications
>> abuse the dumb buffer API to get hold of drm buffers that they can both
>> mmap() and use for GPU acceleration, using the assumptions that dumb buffers
>> and buffers available for GPU are
>> a) The same type and can be aribtrarily type-casted.
>> b) fully coherent.
> Both (a) and (b) are true for intel and it turns out to be a requirement
> for smooth transitions from the boot splash screens into X, and relied
> upon by userspace.
> -Chris
>

So when you say relied upon by user-space, do you mean generic
user-space or driver-specific user-space?

With that, I mean what component is responsible for deciding that the
dumb buffer can be accelerated? The Intel xorg driver?

/Thomas


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  reply	other threads:[~2014-11-21 14:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-20  8:56 [PATCH] drm/gem: Warn on illegal use of the dumb buffer interface v2 Thomas Hellstrom
2014-11-21 14:14 ` Chris Wilson
2014-11-21 14:48   ` Thomas Hellstrom [this message]
2014-11-21 14:51     ` Chris Wilson
2014-11-21 14:59       ` Thomas Hellstrom

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