linux-kernel - Re: [RFC] enhancing the kernel's graphics subsystem

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Message-ID: <9e4733910705281357x592f0853re9492efdb5ef82e8@mail.gmail.com>
Date:	Mon, 28 May 2007 16:57:37 -0400
From:	"Jon Smirl" <jonsmirl@...il.com>
To:	"Pavel Machek" <pavel@....cz>
Cc:	"Dave Airlie" <airlied@...il.com>,
	"Jesse Barnes" <jbarnes@...tuousgeek.org>,
	"Jeff Garzik" <jeff@...zik.org>,
	"Jesse Barnes" <jesse.barnes@...el.com>,
	linux-kernel@...r.kernel.org,
	"Antonino A. Daplas" <adaplas@...il.com>
Subject: Re: [RFC] enhancing the kernel's graphics subsystem

On 5/28/07, Pavel Machek <pavel@....cz> wrote:
> Hi!
>
> > >> These are not isolated problems. Linux needs a
> > >properly designed
> > >> graphics subsystem. One way to achieve that is to
> > >design it all on
> > >> paper first so that we can try and locate the
> > >interactions between
> > >> modules. For example the current mode setting design
> > >is definitely
> > >> broken for multi-seat support, that's because you
> > >didn't take that
> > >> feature into account when writing the code.
> > >
> > >No it isn't the code Jesse posted can handle multi-seat
> > >fine in the
> > >areas that it makes sense as we've pointed out to you
> > >you cannot just
> >
> > The code doesn't create one device per CRTC. Missing
> > that feature
> > means that we need a persistent root priv app around
> > that owns the
> > single device and then listens for messages from each
> > seat asking it
> > to do things. That root priv app is not necessary, it is
> > a security
> > risk and it should be eliminated.
>
> Fine, submit a patch. But don't block other people patches just
> because they do not address your favourite problem.

I have already implemented this once and submitted a patch.

Search in the paper for this paragraph:
http://jonsmirl.googlepages.com/graphics.html
DRM also implements the concept of a master user with more
capabilities than normal users. These extra capabilities allow the
graphics device to be initialized and the consumption of GPU resources
to be controlled. The current X server, which runs as root, functions
as the DRM master. There is actually no real requirement that the DRM
master be run as root, and there is a preliminary patch that removes
this requirement.

That paragraphs contains a link to the code that used to be hosted at
freedesktop.org. Maybe they can still find it.

-- 
Jon Smirl
jonsmirl@...il.com
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