Re: pin OABUFFER to GGTT

[Ben Widawsky <ben@bwidawsk.net>]

On Thu, Jul 03, 2014 at 10:10:48AM -0700, Ben Widawsky wrote:
> On Thu, Jul 03, 2014 at 08:17:32AM +0100, Damien Lespiau wrote:
> > On Wed, Jul 02, 2014 at 02:19:42PM +0100, Rutkowski, Adam J wrote:
> > > Having said all this, how about restoring the pin_ioctl? At least for
> > > some time? We do have a use case and moving to other - better -
> > > solution would take time. I think backward compatibility is something
> > > that you take into consideration as well.
> > 
> > So, I just sent a patch reverting the change. Daniel will have an
> > opinion about this I'm sure, being the original author. Let see what
> > happens when he's back from holidays.
> > 
> > Cheers,
> > 
> > -- 
> > Damien
> 
> Just a note for a future ppgtt people - this adds another way to get
> multiple VMAs for a single BO. To this point, it had only been flink,
> and dmabuf. IIRC there are few unhandled corner cases for this. Also
> note that if the BO is still referenced within a batch, we need the flag
> to tell us it needs global binding.
> 
> FWIW, I remain in favor of the relocation idea unless someone already
> expressed why we need multiple processes to have the relocation info.
> 

I just realized there isn't really a good way to make the buffer persist
at the same offset if we use the relocation method. So I take back the
statement that it's a good idea.

-- 
Ben Widawsky, Intel Open Source Technology Center