Re: [RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging

[Brian Starkey]

Hi,

On Thu, Mar 09, 2017 at 09:38:49AM -0800, Laura Abbott wrote:
> On 03/09/2017 02:00 AM, Benjamin Gaignard wrote:

[snip]

> > For me those patches are going in the right direction.
> >
> > I still have few questions:
> > - since alignment management has been remove from ion-core, should it
> > be also removed from ioctl structure ?
>
> Yes, I think I'm going to go with the suggestion to fixup the ABI
> so we don't need the compat layer and as part of that I'm also
> dropping the align argument.

Is the only motivation for removing the alignment parameter that
no-one got around to using it for something useful yet?
The original comment was true - different devices do have different
alignment requirements.

Better alignment can help SMMUs use larger blocks when mapping,
reducing TLB pressure and the chance of a page table walk causing
display underruns.

-Brian