On Tue, 17 Dec 2019, Lee Jones <lee.jones@xxxxxxxxxx> wrote: > On Mon, 16 Dec 2019, Hans de Goede wrote: > >> Hi, >> >> Doing immutable branches assumes that there is a base point, >> e.g. 5.5-rc1 where the immutable branch can then be based on and >> that the branch can then be merged without issues into both subsystems. >> >> drm is constantly evolving to deal with and mostly catch up with new >> hardware as both GPUs and display-pipelines are evolving quite rapidly >> atm drm-intel-next has about 400 commits on top of 5.5-rc1 so for an >> immutable branch I can either base it on drm-intel-next which >> violates your request for a clean minimal branch to merge; or I can >> base it on 5.5-rc1 which leads to a big chance of problems when >> merging it given to large amount of churn in drm-intel-next. > > This is a *slightly* more compelling reason than the ones you've > previously provided. > >> So instead of the normal case of 2 subsystems seeing some changes >> on both side the case we have here is a part of a file which has >> not changed since 2015-06-26 in one subsys (and changing only >> a single line there!) and OTOH we have bigger changes to a subsys >> which see 400 patches land in the first week since rc1 . > > This is not. > >> I hope that you agree that in this case given the large amount of >> churn in drm-intel-next it makes since to just straight forward >> apply these patches on top of drm-intel-next. > > I have Acked this patch, but remember *this* is the exception rather > than the rule. If/when we have a case where a contributor works > cross-subsystem with DRM and the code/file adapted is live (more > likely to change), I will have to insist on an immutable branch > strategy. DRM will have to deal with that appropriately. Hi, thanks for the ack and reaching an agreement with Hans, and sorry for not responding earlier. It's not unusual for us to have topic branches for cross-subsystem or cross-driver changes, and I think usually we try to be accommodating in merging stuff through whichever tree it makes most sense. In fact my ack to do just that was my first response on this series [1]. So I don't really know why the fuss. We'll anyway deal with any cross-subsystem series on a case by case basis, depending on what makes most sense, and what suits all maintainers involved. Thanks again, Jani. [1] http://mid.mail-archive.com/87pnhnyir8.fsf@xxxxxxxxx -- Jani Nikula, Intel Open Source Graphics Center
