[PATCH 4/5] drm/vgem: getparam ioctl
Adam Jackson
ajax at redhat.com
Wed Feb 15 13:22:10 PST 2012
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 at 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
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