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From: Adam Jackson <ajax@redhat.com>
To: Ben Widawsky <ben@bwidawsk.net>
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 4/5] drm/vgem: getparam ioctl
Date: Wed, 15 Feb 2012 16:22:10 -0500	[thread overview]
Message-ID: <4F3C2202.2050708@redhat.com> (raw)
In-Reply-To: <1328743171-13750-5-git-send-email-ben@bwidawsk.net>

On 2/8/12 6:19 PM, Ben Widawsky wrote:
> Similar to i915, it's nice to be able to query this device uniquely and
> get some info
>
> Signed-off-by: Ben Widawsky<ben@bwidawsk.net>

So, this is actually not especially useful as written.  You'd like to be 
able to use this to find the vgem device node, but since it's a 
device-specific ioctl it collides with whatever happens to be 
device-specific ioctl number 2 on whatever device you've opened.  On 
i915, that's I915_FLIP, and you promptly oops the machine.

Comedy. Gold.

Which is fine, really.  The way I was anticipating finding the vgem node 
was to just scrape the device node name out of 
/sys/bus/platform/devices/vgem/cardN, because why do anything O(n) when 
you could do it O(1).  I guess that doesn't help OSes that aren't Linux, 
and I guess if pressed to care about that I'd say hang it off drm_getcap.

- ajax

  reply	other threads:[~2012-02-15 21:22 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-08 23:19 [RFCv2 PATCH 0/5] virtual GEM provider Ben Widawsky
2012-02-08 23:19 ` [PATCH 1/5] drm/vgem: " Ben Widawsky
2012-02-08 23:28   ` Chris Wilson
2012-02-16 13:52   ` Jakob Bornecrantz
2012-02-20 17:10     ` Ben Widawsky
2012-02-21 15:03       ` Adam Jackson
2012-02-21 15:34         ` Dave Airlie
2012-02-21 16:08           ` Adam Jackson
2012-02-21 17:41             ` Ben Widawsky
2012-02-08 23:19 ` [PATCH 2/5] drm/vgem: fops should be separate and constified Ben Widawsky
2012-02-08 23:19 ` [PATCH 3/5] drm/vgem: Add a drm_vgem_gem_object Ben Widawsky
2012-02-08 23:19 ` [PATCH 4/5] drm/vgem: getparam ioctl Ben Widawsky
2012-02-15 21:22   ` Adam Jackson [this message]
2012-02-16  7:23     ` Dave Airlie
2012-02-20 17:12       ` Ben Widawsky
2012-02-08 23:19 ` [PATCH 5/5] drm/vgem: properly implement mmap Ben Widawsky
2012-02-08 23:36   ` Chris Wilson
2012-02-09  9:18     ` Ben Widawsky
2012-02-09 10:20     ` Daniel Vetter
2012-02-14  2:18   ` Eric Anholt
2012-02-14  7:49     ` Dave Airlie
2012-02-14  0:14 ` [RFCv2 PATCH 0/5] virtual GEM provider Adam Jackson

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