From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Hellstrom <thellstrom@vmware.com>
Subject: Re: The controlD device
Date: Fri, 21 Oct 2011 18:03:27 +0200
Message-ID: <4EA197CF.4080108@vmware.com>
References: <4EA17C66.10207@vmware.com>	<CAPM=9tyithY0uZehptV8AYYwvsnhZR1rFh-Uv=7Pj8Ym4YM2Uw@mail.gmail.com>
	<CAPM=9txbA1o2aP9u4Mk025-46VhUyp9+e0ceMJcCvnbyuuWOKw@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Content-Transfer-Encoding: 7bit
Return-path: <dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org>
Received: from smtp-outbound-1.vmware.com (smtp-outbound-1.vmware.com
	[65.115.85.69])
	by gabe.freedesktop.org (Postfix) with ESMTP id 9188F9E7BA
	for <dri-devel@lists.freedesktop.org>;
	Fri, 21 Oct 2011 09:05:41 -0700 (PDT)
In-Reply-To: <CAPM=9txbA1o2aP9u4Mk025-46VhUyp9+e0ceMJcCvnbyuuWOKw@mail.gmail.com>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/dri-devel>,
	<mailto:dri-devel-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/dri-devel>
List-Post: <mailto:dri-devel@lists.freedesktop.org>
List-Help: <mailto:dri-devel-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/dri-devel>,
	<mailto:dri-devel-request@lists.freedesktop.org?subject=subscribe>
Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org
Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org
To: Dave Airlie <airlied@gmail.com>
Cc: Dave Airlie <airlied@redhat.com>, "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
List-Id: dri-devel@lists.freedesktop.org

On 10/21/2011 04:36 PM, Dave Airlie wrote:
> On Fri, Oct 21, 2011 at 3:18 PM, Dave Airlie<airlied@gmail.com>  wrote:
>    
>> On Fri, Oct 21, 2011 at 3:06 PM, Thomas Hellstrom<thellstrom@vmware.com>  wrote:
>>      
>>> Dave,
>>>
>>> What is the drm control device nodes really used for?
>>>
>>> On my fc14 system it seems like it has world rw privileges, and full access
>>> to all modesetting ioctls.
>>> Is that the intention?
>>>        
>> No, and I just realised we packaged a broken udev rule.
>>
>> It should be root only, oops.
>>
>> Its intention is for setting up multi-seat and gpgpu access to the drm.
>>
>> change /etc/udev/rules.d/91-modeset.rules to be 0600.
>>      
> I've filed updates to Fedora to fix this, no other distro should be
> using or caring about these device nodes yet, since we never really
> got GPGPU going yet.
>
> Dave.
>    
Sounds good. I was actually mostly curios on the intended usage pattern 
of the control node.
I found some things on the DRM wikis, but it doesn't at all seem 
consistent with what's in DRM.

Why do we have CONTROL_ALLOW on all modesetting ioctls?, also this code 
in drm_crtc.c  seems odd:

if (file_priv->master->minor->type == DRM_MINOR_CONTROL) {
...

Isn't that equivalent to

if (file_priv->minor->type == DRM_MINOR_CONTROL) { ?

Any enlightenment would be appreciated.

Thanks,
/Thomas