Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
On 19/06/19 22:19, Simon McVittie wrote: [...] I would very much appreciate input from the rest of the team, particularly: - Laurent: I know you've had strong opinions about using Wayland for GNOME. Do you feel strongly that Debian should be defaulting to Wayland? Are there any reasons for that default that are missing from my attempt to summarize earlier on the bug? [...] I'm personally using wayland for more than 3 years on my work laptop (Intel card) and my home desktop (ATI/AMD with OSS driver) and even if there were transient issues at some point, everything is pretty stable now with 3.30 (the version that will be released with buster). Like Iain the main annoyance I have in my daily use is with the desktop/window sharing in firefox. Wayland has been (re)made the default in debian back in July 2017 (beginning of the dev cycle for buster), I don't remember receiving any objections at the time. The question about using it by default was raised by Jonathan in Apr 2019, two months in the (soft) freeze, it was already quite late at that point IMHO to switch back. This makes me wonder, are there even people using GNOME in sid/testing? Are there people testing with the default settings or has everybody switch back to X11? Because we had a full development cycle and we didn't have a massive number of bugs being filled about this, how should we interpret that? It's also important to note that we are not pioneer in this, Fedora is defaulting to GNOME Wayland since Fedora 25 (Nov 2016). Both RHEL 8 (just released and using GNOME 3.28, so one release lower) and SUSE Linux Enterprise Desktop 15 (released in end of June last year using GNOME 3.26) are also defaulting to GNOME Wayland. We could indeed revert to X11 in a point release if things are going horribly wrong, some first step could be to put more information about this in the release notes. RHEL has https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/8.0_release_notes/index#desktop but I don't think that everything there applies to Debian
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
Preserving the rather large CC list for now… On Thu, Jun 20, 2019 at 06:05:22AM -0400, Sam Hartman wrote: I feel very uncomfortable with a change as big as this revert happening this late in the release cycle. How big is big? The MR I raised resurrects a patch that changes one line of code, and was shipped in the last stable release. Although it looks like further work is needed to make the change as smooth as possible so this would grow. However, the patch certainly needs more testing. Is the issue that it results in a large change in terms of what software is executed by the user as a consequence, and what of that has been tested thus far in the freeze? How late is late? How would you have felt about it back in early April, when I first raised it? I was surprised to discover it then, and I felt it was late in the cycle even then. But mostly whats happened since is nothing. I absolutely do not blame the GNOME team here. Simon McVittie and Michael Biebl in particular have taken risks sticking their heads above the parapet to engage with me on this matter, and both have made it clear that it would be unreasonable for them to make the call given their respective levels of involvement. I respect that, and I am extremely grateful for them engaging with the issue. The others are either too busy or have taken a decision not to engage with a potentially toxic issue, and I respect that, too: we are all volunteers who have to make our own choices about what we are prepared to do and engage in. Besides, like many teams, the GNOME team is clearly under-resourced. I am a *little* disappointed that this does not seem to have been thought of as an important, project-wide issue. Regardless of whether one uses GNOME or Wayland oneself, the matter of the default desktop for the distribution we are all working to produce, and the experience that our users will get out of the box, I would have thought was important for all of us. It reinforces the idea, to me, that we are largely working in our own silos, and not concerned (enough) about the holistic distribution as a whole. And yet, the lack of a clear reconfirmation in this time line even given the wonderfully civil discussion is telling. I'm very pleased that the discussion has come across as civil. I've tried really hard from my end to achieve that, I know that issues around GNOME can result in some very toxic communications. My proposal--which again I have no power to implement--is that we go forward with the current default. However, we remain open to a revert in the first couple of buster point releases. There are caveats with switching the default in either direction. Let's say we go with Wayland now, and later decide to switch as per the criteria/process you sketch below. • users of the default, who got Wayland from Buster onwards and had no problems, would subsequently find themselves switched to Xorg by stable-updates, which IMHO would be unexpected (if noticed) and contrary to the expectations of a stable release. • A user who installed or upgraded and got Wayland by default but had problems, would have likely addressed them by switching to the Xorg session explicitly (assuming they could figure out that doing so mitigated their issues). Changing the default would only prevent *future* users from hitting the same problems. The criteria for that revert should be based on the actual severity and frequence of problems our users run into, but should specifically exclude the blanket reluctance to make a change like that in a point release. We would still need adequate testing of such a revert. My concern with this is it's a new set of policies and procedures, not codified anywhere, with a lot of detail to work out "on the hoof" (how do we measure frequency of problems? do we go with the existing bug severity guidelines? How much is adequate testing? etc.) So combined with the user experience above, I think we would be best not to change the default within a stable release cycle, unless there was some kind of enormous catastrophic issue with Wayland that we don't know about yet, and that's unlikely. I still argue that the traditional Debian conservative, when-its-ready approach would be the distribution status quo (Xorg), but I recognise the concerns about the proposed patch, further work needed, lack of testing etc.; and those are not issues I think I can resolve alone. -- Jonathan Dowland
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
I'm writing with my DPL hat on in the role of a facilitator/mediator. I have no actual power in this situation and it is entirely reasonable to ignore me. I feel very uncomfortable with a change as big as this revert happening this late in the release cycle. I think that my reading of how the release team handles issues is sufficient to say that they almost certainly have serious concerns about that big of a change this late too. And yet, the lack of a clear reconfirmation in this time line even given the wonderfully civil discussion is telling. My proposal--which again I have no power to implement--is that we go forward with the current default. However, we remain open to a revert in the first couple of buster point releases. The criteria for that revert should be based on the actual severity and frequence of problems our users run into, but should specifically exclude the blanket reluctance to make a change like that in a point release. We would still need adequate testing of such a revert. So, what I think this would require to be a viable proposal is: * an ack from the buster stable release managers that if we run into real problems they would accept such a change * an ack from gnome that if we do need to do a revert we'd be willing to revert in unstable and testing for a while to do as much testing of the revert in those environments. Obviously such testing is imperfect given that gnome may (hopefully will) have moved on in Debian by then. Again, feel free to ignore this message entirely if it does not move the conversation forward. I'm just seeing a stuck issue and proposing a way to try and unstick it. --Sam signature.asc Description: PGP signature
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
Hi everyone Am 20.06.19 um 11:12 schrieb Iain Lane: >> I've left some comments on >> https://salsa.debian.org/gnome-team/gdm/merge_requests/8 regarding the >> technical side of the proposed change. > Someone could probably look in Ubuntu's gdm3 package to see what we're > doing. We provide "GNOME" (Xorg, the default) and "GNOME on Wayland" > sessions. Afair, this required changing gnome-session. I left a comment in the gdm MR. If the point is, to not switch the desktop session automatically on upgrades, then the session files would have to be renamed (back again) to gnome.desktop (Xorg) and gnome-wayland.desktop from gnome.desktop (Wayland) and gnome-xorg.desktop. At least this is how I remember the details from back then in 2016. I haven't checked if the situation is still the same today. Regards, Michael -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth? signature.asc Description: OpenPGP digital signature
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
Hi Simon, others, Thanks to those involved so far in shepherding this side of the issue along. And also for poking me (repeatedly!) to reply. On Wed, Jun 19, 2019 at 09:19:49PM +0100, Simon McVittie wrote: > On Wed, 19 Jun 2019 at 17:33:55 +0100, Jonathan Dowland wrote: > > So far as I am aware there is still radio silence from active GNOME > > packaging team members regarding this issue. No comment yet on the > > patch I adapted, positive or negative; this bug (#927667) remains > > at an RC severity. Right, sorry about that. It's a big lack of spoons for me (please consider that if you are thinking about rebutting my points below). I personally find this kind of topic a bit draining, although I appreciate that the temperature of the bug (not the previous -devel thread) is quite low. Thanks for that. > (Adding debian-gtk-gnome, debian-desktop and some people who might have > useful input to Cc) > […] > - Ubuntu GNOME team: which recent Ubuntu versions, if any, are using > Wayland for their GNOME-based desktop? Seb's explained that, and the reasons why that decision was made. So you can have my inconclusive personal opinion: I've been deliberately using Wayland-on-Ubuntu and Wayland-on-Debian the whole time, and the only thing that has irritated *me* was one time I couldn't screen share from Firefox. I *like* that it's raised the bar for privilege separation (the Synaptic case), as I find it quite distasteful to be running the entire thing as root. I acknowledge that the shell-crashing-crashes-the-session model could be uncomfortable sometimes — but my experience has not been one where that happens. Some of the upstream improvements (e.g. fractional scaling, which is still experimental) are Wayland-only. I've read and understood the counter-arguments posted on the bug. I don't feel in a particularly good position with respect to weighing up the balance here. If you are affected by a Wayland-specific bug, especially if it impacts you frequently (e.g. you can't do something you need to do, or the shell repeatedly crashes / the mouse becomes unresponsive / similar), that is going to be really quite irritating. And I share Ansgar's concern about this all being very late now. Part of that is down to our (GNOME team at large) lack of engagement on the bug — apologies again — but it would have felt late to me even at the end of April. That said, Ubuntu has been shipping with this configuration and we don't know of any particular issues. Release team, what do you think? In conclusion, I will not stand in the way of anyone if they want to execute this change, but it's not likely to be me doing it. > I've left some comments on > https://salsa.debian.org/gnome-team/gdm/merge_requests/8 regarding the > technical side of the proposed change. Someone could probably look in Ubuntu's gdm3 package to see what we're doing. We provide "GNOME" (Xorg, the default) and "GNOME on Wayland" sessions. Cheers, -- Iain Lane [ i...@orangesquash.org.uk ] Debian Developer [ la...@debian.org ] Ubuntu Developer [ la...@ubuntu.com ] signature.asc Description: PGP signature
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
Hey there, Le 19/06/2019 à 22:19, Simon McVittie a écrit : - Ubuntu GNOME team: which recent Ubuntu versions, if any, are using Wayland for their GNOME-based desktop? We don't have any supported Ubuntu version using Wayland by default, our motivations for sticking to Xorg were mostly desktop sharing/rdp support and the fact that under wayland a gnome-shell segfault takes the whole session down without giving user a chance to save their work. While screen sharing is being actively being worked on, our metrics show that gnome-shell errors are still quite common, even in recent versions so it's not likely that we change our default for the next LTS. Cheers, Sebastien Bacher
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
On Wed, 19 Jun 2019 at 17:33:55 +0100, Jonathan Dowland wrote: > So far as I am aware there is still radio silence from active GNOME > packaging team members regarding this issue. No comment yet on the > patch I adapted, positive or negative; this bug (#927667) remains > at an RC severity. (Adding debian-gtk-gnome, debian-desktop and some people who might have useful input to Cc) In case anyone else in the GNOME team has got the wrong idea from my involvement in #927667: I don't think I am the right person to make a decision on this. So if GNOME team members are waiting for me to either make an upload changing the default back to X11, or veto such an upload: don't wait for that, it is unlikely to happen (unless the team cannot make a decision and punts this to the technical committee, but I hope we don't have to resort to that). I would very much appreciate input from the rest of the team, particularly: - Laurent: I know you've had strong opinions about using Wayland for GNOME. Do you feel strongly that Debian should be defaulting to Wayland? Are there any reasons for that default that are missing from my attempt to summarize earlier on the bug? - Ubuntu GNOME team: which recent Ubuntu versions, if any, are using Wayland for their GNOME-based desktop? I've left some comments on https://salsa.debian.org/gnome-team/gdm/merge_requests/8 regarding the technical side of the proposed change. Thanks, smcv
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
On Sat, Apr 27, 2019 at 11:49:24PM +0100, Simon McVittie wrote: The status quo of GNOME is that the default *is* Wayland, and if we want the default in Debian to be X11 instead, we have to patch something (as we did in stretch). I firmly believe that distributions sometimes need to diverge from their upstreams, but that any such divergence needs to have a justification, so I could turn this around: what are the criteria that you believe should be used in the decision making for switching to X11-for-default? The direction of travel from an upstream GNOME perspective may indeed be from Wayland-to-X11, but from a Debian release perspective, it's the other way around: X11 is the display technology installed by default in Debian and, due to GNOME's status as the default desktop environment, adopting GNOME's default of Wayland has the wider repercussion of also switching the Debian default. I agree that divergences need justifications, but I also believe we need to be mindful of the whole distribution when considering these matters. It was not clear to me when I started this discussion, and it remains unclarified now, whether due consideration to the distribution as a whole has taken place for Buster. For significant technology changes, Debian has traditionally taken a slow, measured, reasoned and conservative approach to adoption. I think it has come as a surprise to many (most?) developers that we are on course to switch to Wayland at this point. My understanding (again, I am not an expert and I don't have an infallible overview) is that the advantages and disadvantages of Wayland mode by default go something like this. This is an excellent summary, thank you. I agree with all of it. A dimension you have not covered in your summary is regression: whether a given behaviour for GNOME/Wayland is a regression with respect to the behaviour of the default desktop in Debian. This facet is what originally brought the matter to my attention. -- Jonathan Dowland
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
> What I would really like to see, please, is pointers to the criteria used in > the decision making for switching to Wayland-for-default. I cannot give you those criteria. I don't think there was any sort of formal document listing requirements that had to be met, any more than there was for stretch (where we reluctantly decided that Wayland mode had too many issues at that stage, and shipped a version of GNOME for which the upstream default was Wayland mode, but patched it to have X11 as default and Wayland as an option for the adventurous). Laurent Bigonville said on IRC that he was the one who reverted our patch that switched the default to X11 mode, in 2017, so perhaps he can clarify the factors that went into this decision. (Or if you mean the criteria used by GNOME upstream, I suggest asking them.) The status quo of GNOME is that the default *is* Wayland, and if we want the default in Debian to be X11 instead, we have to patch something (as we did in stretch). I firmly believe that distributions sometimes need to diverge from their upstreams, but that any such divergence needs to have a justification, so I could turn this around: what are the criteria that you believe should be used in the decision making for switching to X11-for-default? (I'm not sure which component would need to change if we wanted to go back to the stretch situation: most likely gnome-session, or perhpas gdm3.) My understanding (again, I am not an expert and I don't have an infallible overview) is that the advantages and disadvantages of Wayland mode by default go something like this. You'll notice that many things turn up in both lists, because they're an advantage or a disadvantage or both, depending how you look at them. Advantages of Wayland mode over X11 mode The Wayland protocol is suitable for privilege separation: ordinary apps cannot be keyloggers, or forge input events, or copy each others' window contents. With X11, if a sandboxed app (Flatpak, Snap, etc.) can draw its own windows, then it can spy on other apps or send input to them. Deliberately using a protocol that doesn't have useful privilege separation doesn't necessarily send a great message about the importance we put on privacy/security. - Rebuttal: some X11 apps want to do those things for non-malicious reasons; see below. In principle sandboxing frameworks could filter X11 access with something like Xpra, although I am not aware of a concrete implementation. If the Wayland compositor (GNOME Shell) crashes, that can't result in a lock-screen bypass, because the compositor is the display-server equivalent: if there is a crash bug that is triggerable by an attacker on a locked session, it is denial of service (end of session), which, while undesirable, is less bad than the privilege escalation (ability to see or manipulate unintended windows) that would often be seen when an X11 compositor/WM crashes. - Rebuttal: denial of service is also bad, and crashes can occur for reasons other than malice. There might be performance advantages for native Wayland apps such as GTK3 apps, from being able to use a more direct rendering path that is a better match for how the hardware works. - Rebuttal: many apps aren't native Wayland apps and won't benefit from this. Wayland is relatively new, so perhaps these performance advantages are only theoretical at this stage. Wayland mode has been GNOME's upstream default for several years, so it's what upstream will be expecting, and is the most likely to get useful feedback on bug reports. Full-screen apps (games) can't arbitrarily change your screen resolution, then crash without changing it back. - Rebuttal: they also can't change your screen resolution even if you want them to. There are some X11-specific bugs. - Rebuttal: there are also some Wayland-specific bugs. Advantages of X11 mode over Wayland mode Some X11 apps want to do things that Wayland doesn't normally allow: capture global keyboard shortcuts (which involves doing the same thing a keylogger would do), or create input events (which involves doing the same thing you'd do if maliciously forging input events), or take screenshots or capture video (e.g. for screencasting or screen-sharing) via X11 (which involves doing the same things you'd do if you were maliciously spying on other apps). - Rebuttal: it's good when apps do these things with the user's knowledge and permission, but very bad when they do them maliciously (see above), and the display protocol is not in an a position to judge intent. In Wayland mode, many of these things can be done via D-Bus by a sufficiently-privileged app, and any useful app-sandboxing framework already needs to filter access to the D-Bus session bus anyway; however, this does require code changes in the privileged app. If the X11 compositing manager/window manager (GNOME Shell) crashes, the X server and the X
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
On Fri, Apr 26, 2019 at 11:55:00AM +0100, Simon McVittie wrote: I forgot to mention before that I've been using a usertag to mark Wayland-related bugs: https://udd.debian.org/cgi-bin/bts-usertags.cgi?tag=wayland=pkg-gnome-maintainers%40lists.alioth.debian.org I've usertagged #928002 accordingly. Please usertag any similar bugs that you report or notice. Thanks Simon, hopefully I've just done that for #928030 (filling up / results in wayland session crashing + gdm3 not working until disk space is freed) (Not all of these are regressions that would be addressed by going back to X11.) Perhaps we should use another usertag to separate out those ones, since those are the ones that would be pertinent for this decision. (This would apply to #928002 and #928030). May I propose "x11regression" under the same BTS user? -- Jonathan Dowland
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
On Fri, 26 Apr 2019 at 10:50:10 +0100, Jonathan Dowland wrote: > On the subject of Wayland's readiness to be the default Debian desktop display > system for Buster, I've just filed #928002 to track problems with > drag-and-drop > between X and non-X applications under Wayland (presently filed against > firefox > but I think it probably belongs somewhere else). I forgot to mention before that I've been using a usertag to mark Wayland-related bugs: https://udd.debian.org/cgi-bin/bts-usertags.cgi?tag=wayland=pkg-gnome-maintainers%40lists.alioth.debian.org I've usertagged #928002 accordingly. Please usertag any similar bugs that you report or notice. (Not all of these are regressions that would be addressed by going back to X11.) smcv
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
Folks, On the subject of Wayland's readiness to be the default Debian desktop display system for Buster, I've just filed #928002 to track problems with drag-and-drop between X and non-X applications under Wayland (presently filed against firefox but I think it probably belongs somewhere else).
Re: Bug#927667: gnome: please confirm or revert choice of Wayland for default desktop
Dear Simon, Thanks for taking the time to file this, I had been meaning to in the week leading up to Easter but I was unable to get much computer time. On Sat, Apr 20, 2019 at 08:44:42PM +0100, Simon McVittie wrote: but I think it would be good to reassess the costs and benefits of Wayland vs. X11 by default, and either make a positive decision to keep Wayland as the default, or diverge from upstream and switch back to Xorg by default like Debian stretch and Ubuntu 18.04 did. The decision as to whether GNOME-in-Debian defaults to Wayland or X has repercussions beyond a GNOME perspective, because GNOME is the default desktop for Debian. I think the "bar" that must be met for a change of default display system from X to Wayland for the default Debian desktop is higher than just for GNOME itself: Debian is a rich ecosystem of thousands of packages from lots of communities, including GNOME and others; I believe it's a reasonable expectation of a user that the default desktop system works reliably with the vast majority of packages within our repositories, not just those designed specifically for GNOME. My personal impression of GNOME/Wayland is that it's not up to that standard just yet (I experience lots of problems when I have tried to evaluate it, but I have not yet filed nor investigated each of them further, and I should). But I would worry about making that judgement myself because I'm not at the cutting edge of this area. Ubuntu deciding that it wasn't ready for 18.04 was notable to me; if it wasn't suitable for them, with a narrower focus than Debian, then I would think it not yet suitable for us either. What triggered me to say something was learning that some packages were being autoremoved, with the justification that they don't work well with the (now) default desktop system. "synaptic" was the first, and a very high profile one at that (but I think it has now been patched: #818366); another that I became aware of was "tilde", but I have not performed an exhaustive search and I worry there may be others. I did try "gparted" to be sure that worked (seems to) since that's another "best in class" GUI app which was likely to have the same problems as synaptic. (I realise that it was neither the GNOME team nor the release team that decided a package not working under Wayland should be RC, and that you do not necessarily support that.) What I would really like to see, please, is pointers to the criteria used in the decision making for switching to Wayland-for-default. What was considered important? Is there any consensus with the position I outline in my first paragraph above? Was this decision made before or after Ubuntu abandoned it for 18.04? Do we know what specific criteria Ubuntu used, and how does it differ to ours? From what I have seen or discovered so far, I argue that GNOME-Wayland is not yet a suitable choice for the default desktop, and would suggest the simplest fix would be to revert to GNOME/X11 for Buster and re-evaluate for the next release. (As the maintainer of flatpak in Debian, I would be sad to see us go back to a display protocol where every app can copy other apps' window contents, inject fake input events or be a keylogger... but I'm also aware that some programs rely on X11 not providing meaningful privilege separation, and that the Wayland compositor model exacerbates any bugs that cause GNOME Shell to crash.) I can appreciate your position and the improved secure isolation of independent graphical apps in the Wayland stack is very attractive. I just want to be sure that we as a project are effectively weighing these new advantages against the costs. It's important to me that we are not throwing out packages (and the corresponding work that other developers have put into making Debian as great as possible), or making the experience of using the wealth of packages within Debian less seamless for new users, without being aware at a project level that we are doing it. I have no axe to grind against Wayland and would never say "never" to it. Best wishes -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Jonathan Dowland ⢿⡄⠘⠷⠚⠋⠀ https://jmtd.net ⠈⠳⣄
