miniblog.

This blog post operates on two levels. On a very direct level, I built a desktop machine with an AMD Radeon RX 5600 XT graphics card and I’ve been fighting a rather annoying interaction with dual monitors on Linux. Here’s how it goes: After some defined period of inactivity, the system tries to standby / suspend / turn off both monitors. Both monitors respond to the DPMS commands and briefly blank. After a few seconds, one of them comes on again, quickly followed by the other one, in an arbitrary order. XFCE “helpfully” detects this as a monitor hotplug event and pops open a display configuration dialog. Stepping away to make a coffee now means periodic flickering and coming back to 5 - 10 XFCE monitor configuration dialogs taking over my screen. Very annoying! Googling around finds this Ubuntu issue from 2018 that seems to describe the same problem, but the documented workaround of amdgpu.dc=0 as a kernel parameter does not work. My graphics card decides to go into a glitchfest and the kernel doesn’t even make it past initrd. That Ubuntu issue links to this upstream Freedesktop issue, which is old enough to get migrated to this new Freedesktop issue, where some kind soul has put together a patch that applies cleanly on recent kernels. My understanding is that the monitor starts polling its inputs when it enters a DPMS mode, and the patch adjusts the timeouts on the driver to ignore the polling pulses instead of treating them as hotplug events. So that’s one level: write a blog post, stuff it with enough keywords that other affected users can find it, tell them to USE THE KERNEL PATCH until a fix is integrated into the mainline. A decent public service, but on its own not interesting. On a second level, I’ve recently been experimenting with NixOS as my daily driver and it rises to this challenge in ways that ArchLinux never could.