Re: [PATCH 3/5] update virtio gpu driver: add 3d/virgl support

[Emil Velikov]

On 10 September 2015 at 11:32, Dave Airlie <airlied@xxxxxxxxx> wrote:
>> > --- /dev/null
>> > +++ b/include/uapi/drm/virtgpu_drm.h
>> > @@ -0,0 +1,163 @@
>>
>> > +
>> > +struct drm_virtgpu_3d_box {
>> > +       uint32_t x, y, z;
>> > +       uint32_t w, h, d;
>> > +};
>> > +
>> There was a similar case (multiple variables declared on a single
>> line) in drm core that caused confusion and we broke the 32bit compat.
>> I thought I mention it - not advocating for/against the above declaration.
>
>
> probably should put some newlines alright,
>
>>
>
>> > +struct drm_virtgpu_3d_transfer_to_host {
>> > +       uint32_t bo_handle;
>> > +       struct drm_virtgpu_3d_box box;
>> > +       uint32_t level;
>> > +       uint32_t offset;
>> > +};
>> > +
>> > +struct drm_virtgpu_3d_transfer_from_host {
>> > +       uint32_t bo_handle;
>> > +       struct drm_virtgpu_3d_box box;
>> > +       uint32_t level;
>> > +       uint32_t offset;
>> > +};
>> > +
>> Afaics these seems to be used by the ioctls. If so the current
>> declarations are not 32bit compat safe. Things will also go badly if
>> you consider expanding struct drm_virtgpu_3d_box in the distant
>> future. A u32 pad after bo_handle and a 'pointer' to struct
>
> I'm curious what you think we can add to a 3d box.
>
None from the top of my head I'm afraid. But I'm wondering if one
cannot keep things flexible considering the cost/downside of the
approach is minimal.

> So this one is fine, no need to align it either I don't think, though I
> should confirm that.
>
> Maybe for safety we can pull the other uint32_t above the box.
>
pahole did complain on my system, but please do - was low on caffeine
so I could have botched something.

Regards
Emil
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