Happy American Thanksgiving. While America watches football and eats deep-fried gobbler, we went to the Popeye's drivethru for chicken and I finished updating Fedora on my daily driver, now at version 35 (see our prior review of Fedora 34). As I always point out: while Fedora is a very common distro on OpenPOWER systems, even if you don't necessarily run Fedora yourself the fact that it does run is important, because it tends to be very ahead of most distros and many problems are identified and fixed in it before moving to other less advanced ones. I test it on my 4-core BMC graphics Blackbird and my dual-8 AMD WX7100 GPU Talos II.
F34 was a messy, unpleasant upgrade. I did the update first on my 4-core stock Blackbird, which I try to keep to stock Fedora as much as possible, though I note for the record both the Bird and the T2 are configured to come up in a text boot instead of gdm and I start GNOME manually from there. I strongly recommend this to act as a recovery mechanism in case your graphics card gets whacked by something or other. On Fedora this is easily done by ensuring the symlink /etc/systemd/system/default.target points to /lib/systemd/system/multi-user.target. Once you've logged into the console jump to GNOME with startx (set XDG_SESSION_TYPE to x11 if this isn't already done), or XDG_SESSION_TYPE=wayland dbus-run-session gnome-session if we want to explore the Wayland Wasteland. Since this is a minimal boot I can also do the upgrade at the same text prompt for speed and ensure as little interference as possible. As usual, the process is, from a root prompt:
dnf upgrade --refresh # upgrade prior system and DNF
dnf install dnf-plugin-system-upgrade # install upgrade plugin if not already done
dnf system-upgrade download --refresh --releasever=35 # download F35 packages
dnf system-upgrade reboot # reboot into upgrader
This went much more smoothly than F34, which had some weird conflicts; it was able to get the necessary packages right away and booted into the installer with no issue. Back at the text prompt, we started with Wayland, as I always do to see if it's still going to suck, and I'm still not disappointed. Performance was even worse than F34, it got glitchy just trying to take a grab with gnome-screenshot from the command line (see this Reddit thread) and BMC video (through the on-board HDMI connector) is still stuck at 1024x768. I took this on my Pixel 3 after I got tired of mucking around with it.
As before don't even bother with Wayland on a Blackbird if you don't have a GPU. Xorg worked fine but was still slow like F34 was. I'll get to that in a moment.
Otherwise, in Xorg, the system, Firefox and LibreOffice mostly worked as before modulo the performance problems, which was a relief.
The T2 tends to be a different story because I have this system heavily customized. Additionally, kernel 5.14 has a known problem with AMD Vega cards (add amdgpu.aspm=0 to your kernel command line as a workaround), and 5.15 may have an issue with amdgpu in power saving mode, so watch out for both of these problems depending on your GPU. (At least one user reported having to blacklist the AST BMC, though that wasn't necessary for me.)
The first problem was more elemental, however: after I downloaded the packages and ran the installation, it still came up offering an impossibly old kernel - the same thing I had to work around with updating to F34!
When I selected it, it started Fedora 35, but with this old 5.11-series kernel from Fedora 34. I did a manual grub2-mkconfig -o /boot/grub2/grub.cfg and restarted, and the Petitboot menu (built off the grub configuration) looked sane again. The text boot came up without incident.
Next, the desktop environment. Usually GNOME upgrades break a large number of my cherished extensions. Surprisingly, only Dash-to-Dock broke this time, which I rebuilt from a fork using these instructions. Note, however, that I do have disable-extension-version-validation set to true in dconf-editor which helps avoid a lot of churn.
However, the same GNOME regressions turned up in F35 that were in F34: CTM still makes a mess out of my custom colour profiles (again something like xrandr --output DisplayPort-0 --set CTM 0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1 will fix it, but this changes based on how your monitors are connected, and every time you [re]start GNOME you'll have to do it), colour calibration still crashes with my Pantone huey, and graphics were still awfully slow. This performance problem is once again libgraphene not being properly built to enable SIMD; the fix was made by the maintainer but the Fedora-distributed library doesn't seem to incorporate it properly. I rebuilt it on F35 and put a copy on Github. It will replace the file of the same name in /lib64 (remember to make a backup and don't do this while GNOME is running).
I'll not comment much further about Wayland except to say that it continues to meet my low expectations on the T2, but as it still doesn't support what my work habits require, I still don't use it. But you can, at least if you have a working discrete graphics card and you've updated libgraphene. For me, Xorg forever, I guess.
My conclusion is damning with faint praise: at least it wasn't any worse. And with these tweaks it works fine. If you're on F34 you have no reason not to upgrade, and if you're on F33 you won't have much longer until you have to (and you might as well just jump right to F35 at that point). But it's still carrying an odd number of regressions (even though, or perhaps despite the fact, the workarounds for F35 are the same as F34) and the installation on the T2 was bumpier than the Blackbird for reasons that remain unclear to me. If you run KDE or Xfce or anything other than GNOME, you shouldn't have any problems, but if you still use GNOME as your desktop environment you should be prepared to do more preparatory work to get it off the ground. I have higher hopes for F36 because we may finally get that float128 update that still wrecks a small but notable selection of packages like MAME, but I also hope that some of these regressions get dealt with as well because that would make these updates a bit more liveable. Any system upgrade of any OS will make you wonder what's going to break this time, but the most recent Fedora updates have come off as more fraught with peril than they ought to be.