Re: [RFC v2 1/8] video: tegra: Add nvhost driver

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 11/29/2012 04:47 AM, Thierry Reding wrote:
> On Thu, Nov 29, 2012 at 12:21:04PM +0200, Terje Bergström wrote:
>> On 28.11.2012 23:23, Thierry Reding wrote:
>>> This could be problematic. Since drivers/video and
>>> drivers/gpu/drm are separate trees, this would entail a
>>> continuous burden on keeping both trees synchronized. While I
>>> realize that eventually it might be better to put the host1x
>>> driver in a separate place to accomodate for its use by other
>>> subsystems, I'm not sure moving it here right away is the best 
>>> approach.
>> 
>> I understand your point, but I hope also that we'd end up with
>> something that can be used as basis for the downstream kernel to
>> migrate to upstream stack.
>> 
>> The key point here is to make the API between nvhost and tegradrm
>> as small and robust to changes as possible.
> 
> I agree. But I also fear that there will be changes eventually and 
> having both go in via different tree requires those trees to be
> merged in a specific order to avoid breakage should the API change.
> This will be particularly ugly in linux-next.
> 
> That's why I explicitly proposed to take this into
> drivers/gpu/drm/tegra for the time being, until we can be
> reasonably sure that the API is fixed. Then I'm fine with moving it
> wherever seems the best fit. Even then there might be the
> occasional dependency, but they should get fewer and fewer as the
> code matures.

It is acceptable for one maintainer to ack patches, and another
maintainer to merge a series that touches both "their own" code and
code owned by another tree. This should of course only be needed when
inter-module APIs change; changes to code within a module shouldn't
require this.