On Thu, Sep 15, 2011 at 06:05:46PM +0100, Dave Airlie wrote: > On Thu, Sep 15, 2011 at 5:34 PM, Alex Deucher <alexdeuc...@gmail.com> wrote: > > On Thu, Sep 15, 2011 at 11:45 AM, Jesse Barnes <jbar...@virtuousgeek.org> > > wrote: > >> At XDC this week we discussed merging drivers back into the server > >> tree. One thing I found frustrating about the discussion was that we > >> didn't have a whiteboard nor a list of the pros & cons of such a > >> change. So I'd like to capture that here (from memory) to let us > >> continue the discussion about whether it's worth it or not. > >> > >> Luc, I think you're the most vocal opponent of this move, so I've cc'd > >> you so you can enumerate any issues I've forgotten. > >> > >> Anyway, as I recall, the issues are as follows: > >> > >> Pros: > >> 1) easier to propagate API changes across drivers (just like Linux) > >> 1a) thus easier to change ABI > >> 2) developers focused on driver development now have more incentive > >> to make sure the server works well so regular releases can still > >> happen (i.e. more people working on blockers whether driver or not > >> as releases approach) > >> 3) allows removal of driver compat code for various server versions > >> 3a) thus removes combinations of driver+server that developers > >> have to support & test > >> 4) increased test coverage for the server as users wanting current > >> driver code will be building new servers too > >> > >> Cons: > >> 1) more work for distros to backport just driver changes to old > >> servers (especially if people follow through on (3) above) > >> 1a) if backporting is harder, new hardware support will be more > >> difficult to land in "enterprise" level distros > >> 2) harder for users to just upgrade drivers independently, now > >> they'll have to build the whole server > >> 2a) thus less testing of current driver code from technical users > >> > >> I've already made my views pretty clear; I'd prefer merging the drivers > >> back in. But I don't do as much work on the DIX or DDX as I used to, > >> and lots of others would be affected as well, so I'd like to hear what > >> people think. Have I captured the pros & cons fully? What to distro > >> maintainers think? And driver developers, both input & output? > > > > For me personally, I don't seem much advantage in moving the drivers > > into the xserver. The number of ABI breaks is minimal (usually 1 per > > xserver) and those can usually be fixed within a day or so of the > > breakage. I don't rebuild the xserver nearly as often as I rebuild > > the ddx so it would mean more work to keep up with the xserver changes > > on a regular basis. For unmaintained drivers, this might be an > > advantage, but at this point the unmaintained drivers are just about > > all for hardware >10 years old, so I'm not sure how important it is to > > continue to pretend we still support them. > > > > Additionally, as was shown in Jeremy's slides, the number of changes > > in the Xserver has been going down with each successive release. It > > doesn't seem untenable to keep maintained external drivers in sync. > > > > At the moment I have a large project in the works to redo the driver ABI, > its pretty much an impossible project no matter what happens, its a major > ABI change and will pretty much require major reworks off all the drivers. > > Now I've no idea how to do this with the current model, even with the drivers > merged its going to be a real pain to land, thats if I ever even get > it to a useable > stage.
That should be the subject of a separate discussion then, to avoid the conflation of the two issues. Cheers, Peter _______________________________________________ xorg-devel@lists.x.org: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel