[PATCH] drm/vgem: drop DRIVER_PRIME

Daniel Vetter daniel at ffwll.ch
Thu May 21 08:24:57 PDT 2015

On Thu, May 21, 2015 at 05:03:58PM +0200, Thomas Hellstrom wrote:
> Hi, Rob!
> On 05/21/2015 04:53 PM, Rob Clark wrote:
> > For actual sharing of buffers with other drivers (ie. actual hardware)
> > we'll need to pimp things out a bit better to deal w/ caching, multiple
> > memory domains, etc.  See thread:
> >
> >   https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.freedesktop.org_archives_dri-2Ddevel_2015-2DMay_083160.html&d=AwIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=hZDsGjgypZF71rQfORpnkvT34UoNymdOdW0M3RyIIpQ&s=6QpYr_rF5y3fBjm48gY5zTJp6Fu87bv2HJYGGJ7VX7s&e= 
> >
> > But for the llvmpipe use-case this isn't a problem.  Nor do we really
> > need prime/dri3 (dri2 is sufficient).  So until the other issues are
> > sorted lets remove DRIVER_PRIME.
> >
> > NOTE this ends up leaving some basically dead code for prime import/
> > export (mostly because I was rushing to send this before a meeting).
> What worries me a little is what Daniel brought up in his commit
> message, that let's say in the end people add a reasonable interface to
> dma_buf mmap, vgem also needs a corresponding interface... Makes me
> think that the best solution for now
> is perhaps to revert it.

Yeah if we just drop the prime parts vgem is pretty much only for llvmpipe
and other software renderers. And if we add prime it'd be purely
self-import only which rejects any foreign access and reject any foreign
objects. At least I haven't understood yet why we need to import the
dma-bufs first when we could just directly mmap the passed-in fd ...

Anyway I think removing the dead code makes sense - we can easily
resurrect it with git again. Also the current prime code for vgem doesn't
handle self-imports correctly, so isnt' even really useable for
llvmpipe-on-vgem as-is.
Daniel Vetter
Software Engineer, Intel Corporation

More information about the dri-devel mailing list