Messages in this thread | | | Date | Fri, 5 Mar 2010 07:53:46 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: Making Xorg easier to test (was Re: [git pull] drm request 3) |
| |
On Fri, 5 Mar 2010, Carlos R. Mafra wrote: > > Whereas everytime I wanted to do that with Xorg it was such a pain that > I want to keep away from that mess.
Actually, take it from me: Xorg is _pleasant_ to test these days.
Ok, so that's partly compared to the mess it _used_ to be, but it's really night and day. The whole build system was so incredibly baroque and heavy that you really had to understand it deeply if you wanted to do anything fancy.
And the non-fancy alternative was to just build the whole thing, which took _hours_ even on fast machines because the build system overhead was near-infinite (I dunno, maybe parallel builds could be made to work, but it took more brain-power than I could ever put into it).
These days, there's a few dependencies you need to know about (I do agree that from a user perspective the thing might have been made a bit _too_ modular) but they are generally fairly trivial, and there are scripts to download all the drivers and misc utilities needed.
And the modularization often works: you can often (but by no means always; it does require that the other parts are "close enough" and that there haven't been any major changes) just have the source code to the one driver you care about, and recompile and install just that _single_ driver.
I've done it. It's becautiful when it works. And it's a major pain when you notice it didn't work, and you needed to get the whole server and libdrm trees after all, and now you're not replacing single files any more and have little idea what it will stomp on in your distro.
So it really is very convenient when it works. And X doesn't have thousands of drivers like the kernel (maybe 10-15 that people care about at all, and about three or four that actually really matter), and there are seldom huge changes that affect them all, so the modularization doesn't turn totally crazy.
So I can see where the Xorg people really like their new modular world. It does work, it's _sooo_ much better than the mess it used to be, and the problems are fairly manageable when they do happen.
The modular approach really works very well when there aren't lots of interactions between the modules, and when the modules are few enough that it isn't a total disaster (imagine doing a change that requires changes to all drivers in Xorg, vs doing a change that requires changes to all drivers in the kernel - the modular approach simply wouldn't work for the latter case, because you'd spend all your time just chasing down external users).
That said, the _one_ thing I really wish could be done would be to make it easier to install things side-by-side - and with the modularization, you really do want to do it module-by-module. One of the things that makes it so easy to test the kernel is that when you install one kernel, that doesn't affect the others, and you can go back-and-forth in testing. That's really important, because it makes testing trivial and non-scary even in the presense of issues that makes the new version unusable.
Linus
| |