Linux kernel 5.19.12 'may harm' Intel laptop screens
Remember the bad old days when getting X settings wrong could fry your CRT? They're back, kinda
A bug in version 5.19.12 of the Linux kernel "may harm" screens on laptops powered by Intel's 12th-generation Core processors.
The Alder Lake family of chips are significantly different from earlier Intel generations, and this has caused previous problems in the open source kernel, though those were relatively modest performance degradation. This latest glitch is a bit more serious, causing displays to flash and fail to work.
So much so that Intel kernel engineer Ville Syrjälä raised the alarm over the flaw on the Linux kernel development mailing list, with the following warning:
After looking at some logs we do end up with potentially bogus panel power sequencing delays, which may harm the LCD panel.
Greg, I recommend immediate revert of this stuff, and new stable release ASAP. Plus a recommendation that no one using laptops with Intel GPUs run 5.19.12.
By that, Syrjälä means changes to the kernel for 5.19.12 may cause LCD panels in laptops to be damaged by the way the code controls power to the screen, when used with an Intel Alder Lake processor's built-in GPU. Other generations, such as the 11th gen, may be affected, too.
The makers of the Framework modular user-repairable laptop issued a warning for its users regarding this bug. There is a description of the problem on the Freedesktop Gitlab, too.
Stable kernel lead Greg Kroah-Hartman has already released kernel 5.19.13, which fixes the issue. If you're on the .12 release and using Intel silicon, you should move off it to .13 and later, or earlier than .12.
The big regular-release distros mostly haven't adopted 5.19 yet, although it came out back in July and has already been superseded by the shiny new kernel 6.0. Users of rolling-release distros such as Arch have it, though. Arch derivative Manjaro Linux has decided to skip from 5.19.7 straight to the newer, fixed version. As kernel.org shows, although version 5.19 is the current stable version, the current long-term kernel is 5.15, as used in Ubuntu 22.04. The next intermediate release of Ubuntu is expected later this month, and is expected to use 5.19, but will surely choose the fixed release.
But if you're using one of the replacement kernels, for example the Liquorix or XanMod kernels we looked at early in the year, this could affect you. The symptoms are intermittent very bright flashes from the LCD's backlight, as shown in the video below, due to an issue in the power management.
Even if your shiny new laptop has a discrete GPU, the Intel integrated one is still in overall control, so we recommend updating the kernel ASAP – or going back to an older version. ®