On 06/07/2011 08:03 PM, Matthew East wrote: > On 7 June 2011 10:02, Alan Bell <[email protected]> wrote: >> yeah, I would very much hope that lightdm does not introduce more >> accessibility regressions. > I'm taking this opportunity to post a link to this comment on the > proposed switch to lightDM from Matthew Garrett, in case people > reading here haven't seen it, it seems relevant to this discussion and > I haven't seen it mentioned before. > > It also briefly discusses impact on accessibility, albeit without > going into detail. > > http://mjg59.livejournal.com/136274.html > Needless to say, I disagree with most of the points Matthew has raised. :)
The argument that LightDM does less because it is smaller is weak. The features listed as missing are the ones currently provided by GNOME session. However, you could very easily write a LightDM greeter that ran a GNOME session (i.e. just copy the relevant code from GDM) that would provide all that same functionality for almost no significant additional lines of code (as the lines are all external modules). So LightDM could provide all the same functionality as GDM with it's current size. However, if you produce a greeter that does implement this functionality by the numbers given in the blog post you would have a whopping 49,000 lines of code to use before you became bigger than GDM. My preferred design is not to use GNOME session, with the main reasons being startup cost, complexity and the security risks of running a full session in a login screen (as pointed out by Chris earlier in this thread). However, the assumption seems to be this will involve rewriting every service. Not the case; of course a GNOME greeter would leverage as much as is appropriate of the GNOME platform e.g. using gnome-power-manager if that was the best solution. A point that is incorrect (which I pointed out to Matthew but he didn't correct) is things like power management are not performed in the backend. So the backend is not going to swell to support different desktops. Sharing policy between login screen and session is up to the greeter. A GNOME greeter should have the same policy as a GNOME session. It wont be the same as KDE policy. Finally I think Matthew massively underestimates the value of being able to differentiate on the greeter. A number of projects - including Ubuntu - have wanted to have a greeter that matches their desktops but have been unable to do so with GDM. No-one really cares (or wants to know) how the lower layers of display management work (I certainly didn't), they just want to work on the GUI. If we were to modify GDM to provide the UI we want (has been attempted a few times) we would be carrying a huge patch on top of the already 35 we are carrying in Natty. Using LightDM we are able to run the daemon unpatched and differentiate to our hearts content with the greeter. With GDM we would effectively be forking the project. -- ubuntu-desktop mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-desktop
