Kernel

A patch series on top of a fixed upstream base. There is no kernel fork: clone the base, apply patches/ in order, build.

For reviewers#

The series by subsystem. Origin, author and status of each patch: PROVENANCE.md.

The Status column of PROVENANCE.md says where a patch stands upstream:

"0115" is missing on purpose: it is a debugging aid kept out of the series.

Base#

• Upstream: torvalds/linux v7.3-rc4 (93f51579e7df248780214094418f205253383cc5).
• Carried on top, as patches in this series: the qcom arm64-for-7.4 kaanapali GPU device tree (0001-0006), picks from the kaanapali-mainline community tree (0007-0011), linux-next next-20260925 picks (0012-0018), and further community / mailing-list work — every patch's origin is listed in PROVENANCE.md.

Reproduce the tree#

git clone --depth 1 -b v7.3-rc4 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux-tb323fu
cd linux-tb323fu
git am /path/to/tb323fu-linux/kernel/patches/*.patch        # 0001 ... 0130, in order (no 0115)

Configuration#

config/ holds:

The same fragments are also added to the tree by patch 0055 (arch/arm64/configs/). The copies here have CONFIG_INITRAMFS_SOURCE blanked — set it to your own initramfs (built with initramfs/build.sh); the version inside patch 0055 still names the path of the original build machine.

What baldur-netfilter.fragment enables

iptables-nft's nft_compat, xt matches, REJECT/rpfilter and ipset. The first part is =m only and can be added to an existing build without a new Image. The second part (NFT_FIB_IPV6/NFT_FIB_INET for firewalld's IPv6 rpfilter, NF_CT_NETLINK, conntrack mark, redirect, the nft bridge and netdev families) changes vmlinux and the core netfilter modules, so it needs a new Image and the whole matching modules set. Still off: legacy iptables tables, conntrack zones/labels, ARP tables.

kaanapali-oneplus-infiniti_defconfig is itself a fragment on top of the arm64 defconfig, so the order is:

make ARCH=arm64 LLVM=1 O=out defconfig
C=/path/to/tb323fu-linux/kernel/config
scripts/kconfig/merge_config.sh -m -O out out/.config \
    arch/arm64/configs/kaanapali-oneplus-infiniti_defconfig \
    $C/baldur.fragment $C/baldur-display.fragment $C/baldur-netfilter.fragment \
    $C/baldur-extra.fragment
make ARCH=arm64 LLVM=1 O=out olddefconfig
make ARCH=arm64 LLVM=1 O=out -j"$(nproc)" Image dtbs modules

Out-of-tree module#

The speakers need the Awinic aw882xx amplifier driver, which is not in upstream Linux. Its GPL-2.0 source is in out-of-tree/aw882xx/; build it against the same kernel build and install it in extra/:

make -C linux-tb323fu O=out ARCH=arm64 LLVM=1 M=$PWD/kernel/out-of-tree/aw882xx CONFIG_SND_SOC_AW882XX=m modules
# -> snd-soc-aw882xx.ko into /lib/modules/<release>/extra/, then depmod

Device tree#

dts/ has the board files as they are after the whole series is applied (they are added by patches 0054, 0064, 0078, 0095 and 0108): kaanapali-lenovo-baldur.dts (the board), kaanapali-lenovo-baldur-display.dts (the one the tested kernel uses), kaanapali-lenovo-baldur-kexec.dts, and the baldur-*.dtsi pieces they include. The SoC side (kaanapali.dtsi) comes from upstream plus the series.

Built-in device tree and fixed command line#

The bootloader on this tablet cannot be made to pass our device tree or command line, so the kernel carries both:

• Built-in DTB (patch 0021, CONFIG_ARM64_BUILTIN_FDT=y, CONFIG_ARM64_BUILTIN_FDT_NAME="qcom/kaanapali-lenovo-baldur-display.dtb"): the kernel ignores the DTB the bootloader hands over and uses the one linked into the Image.

• Fixed command line (CONFIG_CMDLINE_FORCE=y): the command line in the boot image header is ignored. The tested kernel uses:

  icc-rpmh.qos_disable=1 icc_rpmh.qos_disable=1 fw_devlink.sync_state=timeout fbcon=font:TER16x32 panic=10 oops=panic
  console=tty1 keep_bootcon qcom_scm.download_mode=full baldur.end=hold consoleblank=120 no_console_suspend
  mem_sleep_default=s2idle cpuidle_psci_domain.allow_cluster_off=0 baldur.diag=0

  Why each option is there

  Option	Why
  icc-rpmh.qos_disable=1, icc_rpmh.qos_disable=1	leave the interconnect QoS settings the bootloader programmed (built-in and module spelling)
  fw_devlink.sync_state=timeout	let providers finish sync_state after a timeout even if a consumer never probes
  fbcon=font:TER16x32	a readable console font on the 3040x1904 panel
  panic=10, oops=panic	reboot 10 s after any oops/panic instead of hanging
  console=tty1, keep_bootcon	kernel messages on the panel, keeping the early boot console
  qcom_scm.download_mode=full	on a crash, stop in the Qualcomm dump mode so a full memory dump can be taken
  baldur.end=hold, baldur.diag=0	knobs of the initramfs /init: baldur.end=hold = normal boot with root selection; baldur.diag=0 is obsolete and ignored — see initramfs/README.md
  consoleblank=120	blank the text console after 2 minutes
  no_console_suspend	keep the console alive across suspend (debugging)
  mem_sleep_default=s2idle	the only system sleep state this platform supports
  cpuidle_psci_domain.allow_cluster_off=0	patch 0118: no CPU cluster idle state in runtime idle, which avoids the resets it caused when idle (3 h without one vs 2 in 78 min, same display-off power); the cause in the cluster's power-down is not fixed, and s2idle still uses the state. 1 = upstream behavior; can be switched at run time in /sys/module/cpuidle_psci_domain/parameters/allow_cluster_off

The kernel on the development tablet#

The kernel running on the development tablet (config: config/reference.config) is this series (0001-0118, no 0115) plus test-only changes that are not part of the series:

• a knob exposing experimental panel modes (vendor 144/165 Hz and a 143 Hz variant; only 90 and 164 Hz are in the series, 0109),
• an idle-state flight recorder for crash analysis, and a knob that adds a delay in the cluster idle path (used to narrow down the idle resets),
• modem (MPSS) device tree nodes, and remoteproc knobs used to investigate GNSS (the tablet appears to have no usable GNSS antenna),
• a q6apm change that polls for the audio framework instead of a fixed 5 s wait (an upstream candidate, not yet in the series).

Default knobs in the series: the idle refresh rate policy is automatic (msm.idle_refresh_policy=2, patch 0110); the CPU cluster idle states are refused in runtime idle (cpuidle_psci_domain.allow_cluster_off=0 on the built-in command line, patch 0118) — it avoids the idle resets that state caused, without fixing their cause; set /sys/module/cpuidle_psci_domain/parameters/allow_cluster_off to 1 to use them again. All of it is built from one tree (no out-of-tree rebuilds of in-tree drivers any more); the only out-of-tree module is the aw882xx speaker amplifier driver, installed in /lib/modules/<version>/extra/ (source and build: out-of-tree/aw882xx).

Licensing#

Patches and kernel sources are GPL-2.0-only (device trees keep their own SPDX identifiers). Imported patches keep their authors and Signed-off-by lines.