[Intel-gfx] [PATCH 10/12] drm: Don't allow multiple buffers fb with stereo modes

Ville Syrjälä ville.syrjala at linux.intel.com
Tue Sep 17 06:32:59 PDT 2013

On Tue, Sep 17, 2013 at 02:20:41PM +0100, Damien Lespiau wrote:
> On Tue, Sep 17, 2013 at 12:37:48PM +0200, Daniel Vetter wrote:
> > I guess we should start to check that. For 3d framebuffers with 2
> > separate buffer handles for each plane I think we need to add another flag
> > to addfb2, e.g.
> > 
> > #define DRM_MODE_FB_3D_2_FRAMES (1<<1) /* separate left/right buffers, doubles plane count */
> > 
> > and then also throw in the respective check code into the core that
> > userspace supplies sufficient amounts of buffers in framebuffer_check()
> > by adjusting drM_format_num_planes and drm_format_plane_cpp.
> Would we really need that flag? we can just count the number of buffers
> and decide from that number whether we're in the 1 or 2 buffer(s) case?

I'd go with explicit flags. We have one for interlaced already. Although
ATM the interlaced flag must mean that the fields are interleaved in the
same buffer. But if we want separate buffers for each field, we need a
flag for that too. Or we just pretend the old interlace flag doesn't
exist yet and steal it for that purpose. I don't think anyone is using
the flag yet. But anyway we'd need a new ioctl :(

Ville Syrjälä
Intel OTC

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