Qualcomm Snapdragon X Elite support meta-issue

[JamiKettunen]

At this point booting my Asus Vivobook S15 (S5507QAD) laptop really isn't missing all that much from Chimera Linux side so at last I'll collect everything related to supporting these devices here. So far I've been running a hacked-together setup documented on https://gist.github.com/JamiKettunen/7c2a25688976c09af819eebc9fbb8396 (which @wezm at least has also been testing thus far on the Lenovo Yoga Slim 7x) but mainline support has come a long way since I initially booted Chimera on these almost a year ago now.

Bootable aarch64 live ISO

• Linux 6.16 kernel (b8bf046) with CONFIG_INTERCONNECT_QCOM_X1E80100=m & CONFIG_IOMMU_DEFAULT_DMA_STRICT=y set to make it actually boot on the Snapdragon X Series platforms
  • Upstream-supported devices: https://github.com/search?q=repo:torvalds/linux+path:arch/arm64/boot/dts/qcom/x1*.dts
• Backport soc: qcom: mdt_loader: Deal with zero e_shentsize to fix firmware loading (or just wait for v6.16.6+ which hopefully unbreaks the stable release)
• Requires modprobe.blacklist=qcom_battmgr on kernel cmdline to avoid early-dev-trigger failing due to missing upstream aDSP linux-firmware of all devices except Lenovo; I'd say early-dev-trigger failure could be made non-fatal but maybe that's a bad idea..
  • https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/qcom/x1e80100
  • https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/qcom/x1p42100
• Making Limine auto-detect devicetree blob to use via dtbloader as drop-in EFI driver (https://codeberg.org/Limine/Limine/issues/4)
  • Current drafted workaround: Snapdragon X Series SoC devicetree-based support for aarch64 chimera-live#29
• initramfs-tools 0.149+ (main/initramfs-tools: update to 0.150 #4642) to include e.g. panel_samsung_atna33xc20 into generated initrd by default
• Limine 9.5.4+ (main/limine: update to 9.6.1 #4641) to fix very long startup delay each time due to the bootloader previously probing for internal SPINOR firmware partitions while looking for EFI system partition etc.
  • The issue is back again as of 9.6.6+: https://codeberg.org/Limine/Limine/issues/22
    • Fixed with https://codeberg.org/Limine/Limine/commit/42e5fb9ded30a52bec4dc39c1a8d7bd91c32aadb

Post-install

• Figure out integration for something to ease extracting firmware from Windows dual-boot install like https://git.launchpad.net/ubuntu/+source/qcom-firmware-extract/tree/qcom-firmware-extract
  • Unfortunately the files are signed per-device and unavailable (with the exception of Lenovo so far) under a proper license for redistribution in linux-firmware while still required for GPU acceleration, charging, battery statistics, proper USB-C support etc.
    • https://git.codelinaro.org/stephan.gerhold/linux/-/commit/7c2a8201 could alleviate this somewhat for most devices (still no GPU accel without zap shader outside EL2 which on the other hand requires an older tcblaunch.exe from Windows + https://github.com/TravMurav/slbounce etc setup)
• Need to write some WoA-specific documentation to setup https://github.com/TravMurav/dtbloader which makes all EFI bootloaders just work (without having to fiddle with defining a per-bootloader devicetree to load that is)
  • I've got wip local packaging and kernel.d script to copy latest timestamp kernel DTBs over to ESP; later something similar to U-Boot's fdtdir is planned to be implemented (and standardized in https://uapi-group.org/specifications/specs/boot_loader_specification)