On Fri, 13.05.11 14:59, Robert Ancell ([email protected]) wrote: > I'm proposing LightDM [1] as a replacement for GDM. I started the > proposal for this in GNOME 3.0 [2] but due to the young age of the > project I thought it better to wait until 3.2 before making a full > proposal. This is it. I apologise this has been done after the > proposal period. > > Why replace GDM? > > - LightDM is a cross-platform solution. Ubuntu is planning to switch > to it this cycle, and other distributions have expressed interest in > the project. By sharing this piece of infrastructure GNOME can spend > more time working on important GNOME components.
I am pretty sure more platforms currently use GDM than use lightdm, how can you claim this as a reason that lightdm was better? In fact, what you claim here could be used as a good reason to convince Ubuntu to use GDM, since that is what the majority uses, not as a reason to convince the others to use lightdm, since that is only used by one relevant distro so far, Ubuntu? > LightDM is aligned with freedesktop.org. What is this supposed to mean? > - I am confident that the LightDM architecture is simpler than GDM. > Some indicators of this: > - Smaller code size > - Well defined interface between greeter and session > - Less dependencies > - Less internal interfaces But do you support everything that gdm supports, too? Like all the a11y stuff? Or the fprint auth, the extensibility and stuff like that? > - By having a well defined interface between the greeter and daemon, > it is significantly easier to develop a greeter without knowledge of > how display management works. This is useful as the skillset and > motivations of these two sets of developers are different. But why is that a benefit? I think we want one good one, instead of a lot of bad ones? Modern forms of authentication, like the biometric stuff, or auth tokens usually need some kind of specific UI integration. Why do you think that it is in our interest to complicate that even further, by requiring that 10 greeters need to be updated for this, instead of just one? > - LightDM is a platform for future work and is investigating the use > of new technologies like Wayland. Hey, that's a non-issue. Grand plans don't count. The gdm devs can promise us Skynet integration and they could be as convincing with that as you are as with a promise of Wayland integration. In general I do believe it is completely OK to replace existing components with complete rewrites from time to time. I have pushed that through myself more than once. But if you do you better have your arguments ready for this. You must have a very good case. You must support everything the old software you are replacing can provide, or have very good reasons why you do not want to support specific features (I have not seen such a list from you). You must support a lot of new features. You must have made clear that you fully understood the problem, you must show that you tried to fix the existing component, or you must have a good reason why you think the current solution is so broken that there is no value in trying to fix it. You must be able to deal with criticism and respond to it. You must show that you can rethink the set of problems, and that you have a good idea where you want to go with this. You need a vision. Right now the only benefit I can see with lightdm is that it allows writing greeters in Qt more easily. I am not sure why that would be interesting to GNOME however. In fact I believe a goal of GNOME should be to head for stricter vertical integration of the platform, not to make balkanization even easier. I too believe the gdm source code is not as simple as it could be. But I think lightdm mostly trades features against simplicity here. And the features you drop are not crazy features that nobody will mind, they are core features, they are features we want and that took us a long time to get. In line with my work on systemd and related techs I have quite a number of things I'd like to see improved in gdm. For example, I want the login screen to show up during early boot. I want background auto-logins with foreground auth queries (i.e. what Alex already suggested here). I want automatic multi-seat. I want hotplug support. I want things to be more dynamic. I want more flexible auth mech support, I want stronger Ply integration. If want soft session switching. But lightdm does not offer any of this, and doesnt make anything of this easier to implement. In fact it puts us even further away from it. Progress might require rewriting components, but just rewriting things is not automatically progress. gdm might not be perfect software. But it is powerful software, and its problems can be fixed in an evolutionary, not a revolutionary way. Lennart -- Lennart Poettering - Red Hat, Inc. _______________________________________________ desktop-devel-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/desktop-devel-list
