Last Minute Linux 6.6 Fixes Address Nine "Unusable" Lenovo AMD Laptops

Linux 6.6 is set to be released as stable this weekend unless Linus Torvalds has reservations and decides to extend the cycle by one week. In any case there are some last minute fixes heading in to fix-up nine different Lenovo laptops with AMD Ryzen SoCs to make the hardware more usable under Linux.

Red Hat engineer Hans de Goede sent out a single patch as the last of the platform-drivers-x86 work ahead of the Linux 6.6 stable release. The patch is extending the DMI quirks table for making nine Lenovo laptops behave properly during suspend/resume under Linux.

When suspending to idle and resuming on select Lenovo laptops with Mendocino APUs, there are multiple NVMe IOMMU page faults after which the system is unstable afterwards until being rebooted. This issue has been tracked in bug reports such as kernel bug 218024.

The affected Lenovo laptop models include:

- LENOVO 82YT / V14 G4 AMN
- LENOVO 83GE / V14 G4 AMN
- LENOVO 82YU / V15 G4 AMN
- LENOVO 83CQ / V15 G4 AMN
- LENOVO 82VF / IdeaPad 1 14AMN7
- LENOVO 82VG / IdeaPad 1 15AMN7
- LENOVO 82X5 / IdeaPad 1 15AMN7
- LENOVO 82XN / IdeaPad Slim 3 14AMN8
- LENOVO 82XQ / IdeaPad Slim 3 15AMN8

These models all need the same s2idle bug quirk to workaround the NVMe s2idle suspend/resume errors.

Separately via the x86/urgent branch is another patch to improve the support for these laptops. Thomas Gleixner explained in that pending patch to skip probing when ACPI/MADT advertises PCAT compatibility:

"David and a few others reported that on certain newer systems some legacy interrupts fail to work correctly.

Debugging revealed that the BIOS of these systems leaves the legacy PIC in uninitialized state which makes the PIC detection fail and the kernel switches to a dummy implementation.

Unfortunately this fallback causes quite some code to fail as it depends on checks for the number of legacy PIC interrupts or the availability of the real PIC.

In theory there is no reason to use the PIC on any modern system when IO/APIC is available, but the dependencies on the related checks cannot be resolved trivially and on short notice. This needs lots of analysis and rework."

This takes care of an issue that multiple AMD Lenovo laptop keyboards do not work under Linux.

Hans de Goede wrote back in the platform-drivers-x86 fix pull:

"I decided to send this in at the last minute because together with "x86/i8259: Skip probing when ACPI/MADT advertises PCAT compatibility" which is pending in tip x86/urgent this fixes a whole group of 9 Lenovo AMD Mendocino Soc based laptop models from being unusable with Linux to them working fine with Linux."

So with the Lenovo laptop models mentioned above, Linux 6.6 should be playing nicely with the hardware while the patches should also work their way back-ported to existing stable kernel series too.