Continuing the discussion from Building HailoRT on Slackware AArch64 Linux:
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SAIRPi Project - Slackware AI on Raspberry Pi
HAILO BUILD DEVELOPMENT DOCUMENTATION
Platform : Raspberry Pi 5 (AArch64 / armv8)
OS : Slackware AArch64 -current
Hardware : Hailo-10H M.2 AI Accelerator Module
Linux : kernel 6.18.26
HailoRT : v5.3.0
This document records all issues, patches, source modifications, cmake flag
decisions, workarounds and findings encountered during the HailoRT build
process on Slackware AArch64. Warts and all.
Maintainer: sairpi.project@penthux.net
Updated : 2026-05-06
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BACKGROUND
This is the first known build of HailoRT for Slackware AArch64 Linux on a
Raspberry Pi 5. It has proven not to be a straight-forward build process.
Currently, the HailoRT source requires cmake 3.3x to build. Slackware AArch64
has cmake 4.3.x installed which is incompatible with cmake 3.3. Any attempts
to build HailoRT software using cmake 4.3.x result in terminal errors which
crash the compile process.
The build environment is a Slackware AArch64 chroot thatās been constructed
and is managed by a SAIRPi.SlackBuild script process. We chose this specific
route in order to isolate R&D and not impact on the host system. It has been
a rolling ātest and verify affairā because weāre in uncharted territory as
far as building HailoRT on Slackware AArch64 is concerned.
This document covers the work weāve engaged in and undertaken to successfully
build HailoRT and PCIe drivers for the Hailo-10H M.2 AI Accelerator Module on
the Raspberry Pi 5 running Slackware AArch64 Linux.
BUILD SYSTEM OVERVIEW
Two-stage build process:
STAGE 1 - Host system (/tmp/_SAIRPi.SlackBuild/SAIRPi.SlackBuild):
- Downloads RPi Linux kernel source, boot-firmware, HailoRT, HailoRT drivers
- Downloads and installs Slackware AArch64 packages into chroot
- Copies _HAILO.SlackBuild scripts into chroot
- Mounts chroot virtual filesystems
- Invokes hailo.SlackBuild inside chroot
STAGE 2 - Chroot environment (/tmp/sairpi-chroot/_HAILO.SlackBuild/hailo.SlackBuild):
- Builds legacy cmake 3.31.12 (required for HailoRT)
- Builds RPi Linux kernel (bcm2712_defconfig, Image.gz, DTBs, modules, headers)
- Builds HailoRT runtime library (libhailort)
- Builds HailoRT PCIe driver (hailo1x_pci.ko)
- Builds HailoRT integrated NNC driver (hailo_integrated_nnc.ko)
- Packages RPi boot firmware blobs (config.txt.new included)
- Downloads and packages Hailo-10H device firmware from Hailo AWS S3
DIRECTORY STRUCTURE
_SAIRPi.SlackBuild/ - Stage 1: host-side orchestrator
SAIRPi.SlackBuild - Stage 1 entry point
.settings.inc - Stage 1 configuration
.functions.inc - Stage 1 shared functions
.build-date - Build datestamp (auto-generated)
get-linux-kernel-source.sh - Downloads RPi Linux kernel source
get-boot-firmware-rpi.sh - Downloads RPi boot firmware source
get-hailort-source.sh - Downloads HailoRT source
get-hailort-drivers-source.sh - Downloads HailoRT drivers source
chroot-get-syspkg.sh - Fetches SARPi board support packages
chroot-pkg-forge.sh - Downloads/installs Slackware pkgs into chroot
pkg/ - SARPi BSP packages (kernel, modules, etc.)
BuildLogs/ - Build log archive
LICENSE - MIT LICENSE
_HAILO.SlackBuild/ - Stage 2: chroot-side builder
hailo.SlackBuild - Stage 2 entry point
.settings.inc - Stage 2 configuration
.functions.inc - Stage 2 shared functions
build-legacy-cmake-source.sh - Builds cmake 3.31.12 from source
build-linux-source.sh - Builds RPi Linux kernel
build-hailort-source.sh - Builds HailoRT runtime libraries
build-hailort-drivers-source.sh - Builds HailoRT PCIe and NNC drivers
build-boot-firmware-rpi.sh - Packages RPi boot firmware blobs
build-hailort-firmware-rpi.sh - Downloads and packages Hailo-10H firmware
config.txt.new - RPi 5 config.txt (installed by boot firmware pkg)
patch/
hailort-protobuf-cmake-aarch64-lib64.patch - Fix protobuf lib64 path on AArch64
hailort-drivers-del-timer-sync-kernel-6.15.patch - Fix del_timer_sync kernel 6.15+
patch_desc.log - Patch descriptions log
HAILO_BUILD_DEV_DOC.txt - This document
HAILO_AFTERBUILD_TEST.txt - Post-build test documentation
LICENSE - MIT LICENSE
ISSUE 001 - cmake 4.x INCOMPATIBILITY WITH HailoRT
Date : 2026-04-26
Status : RESOLVED via legacy cmake 3.31.12
Severity: CRITICAL - terminal error
Description:
Slackware AArch64 current ships cmake 4.3.2 (/usr/bin/cmake). HailoRT
requires cmake 3.x. cmake 4.x removed the protobuf_generate_cpp() command
which HailoRT uses in:
hailort/common/genai/serializer/CMakeLists.txt:5
Error seen with cmake 4.x:
CMake Error at hailort/common/genai/serializer/CMakeLists.txt:5
(protobuf_generate_cpp): Unknown CMake command āprotobuf_generate_cppā.
Resolution:
Build and install cmake 3.31.12 from source as a legacy cmake alongside
the system cmake 4.3.2. cmake 3.31.12 installs to /usr/local/cmake-3.31/.
Three mechanisms ensure cmake 3.31.12 is used instead of 4.3.2:
-
Symlink: /usr/local/bin/cmake ā /usr/local/cmake-3.31/bin/cmake
/usr/local/bin is before /usr/bin in PATH, so cmake 3.31.12 is always
found first. -
Explicit PATH export in hailo.SlackBuild:
export PATH=ā/usr/local/cmake-3.31/bin:${PATH}ā
Guarantees cmake 3.31.12 is first in PATH for the automated build and
all child processes. -
cmake-legacy.sh profile script sourced at chroot entry:
[ -f /etc/profile.d/cmake-legacy.sh ] && . /etc/profile.d/cmake-legacy.sh
Written to chroot by SAIRPi.SlackBuild (host side). Ensures cmake 3.31.12
is in PATH for all shell types when entering the chroot manually.
cmake 3.31.12 confirmed active:
$ cmake --version
cmake version 3.31.12
Files modified:
_HAILO.SlackBuild/build-legacy-cmake-source.sh - builds cmake 3.31.12
_HAILO.SlackBuild/.settings.inc - CMAKE_LEGACY_VER, CMAKE_LEGACY_INSTALL_DIR
_HAILO.SlackBuild/hailo.SlackBuild - PATH export
_SAIRPi.SlackBuild/SAIRPi.SlackBuild - writes cmake-legacy.sh to chroot
ISSUE 002 - protobuf_generate_cpp NOT DEFINED (AArch64 lib64 path issue)
Date : 2026-04-26
Status : RESOLVED via patch + automated patch application
Severity: CRITICAL - terminal error
Description:
Even with cmake 3.31.12, cmake configure failed with:
CMake Error at hailort/common/genai/serializer/CMakeLists.txt:5
(protobuf_generate_cpp): Unknown CMake command āprotobuf_generate_cppā.
Root cause:
HailoRT uses FetchContent to download and build protobuf v21.12 from source.
After building, it attempts to include protobufās cmake config files to
obtain the protobuf_generate_cpp() macro:
hailort/cmake/external/protobuf.cmake lines 48-49:
include(/usr/src/hailort/hailort/external/protobuf-install/lib/cmake/protobuf/protobuf-config.cmake)
include(/usr/src/hailort/hailort/external/protobuf-install/lib/cmake/protobuf/protobuf-module.cmake)
The protobuf install path is hardcoded in protobuf.cmake as:
/usr/src/hailort/hailort/external/protobuf-install/lib/cmake/protobuf
However on AArch64 Linux, protobuf installs its cmake config files to
lib64/ not lib/:
ACTUAL: /usr/src/hailort/hailort/external/protobuf-install/lib64/cmake/protobuf/
EXPECTED: /usr/src/hailort/hailort/external/protobuf-install/lib/cmake/protobuf/
The include() calls silently fail (path not found), protobuf_generate_cpp()
is never defined, and cmake errors out when it encounters the call.
NOTE: Hailo will be notified of this issue. The comment in protobuf.cmake
line 36 reflects the related issue:
TODO: consider importing protobuf_generate_cpp instead?
Resolution:
Patch hailort/cmake/external/protobuf.cmake to detect lib64 first on
non-Windows platforms, falling back to lib if lib64 does not exist.
Patch file:
_HAILO.SlackBuild/patch/hailort-protobuf-cmake-aarch64-lib64.patch
Patch applied automatically in build-hailort-source.sh before cmake
configure. Uses --forward flag so it is safely skipped if already applied.
Patch diff:
ā a/hailort/cmake/external/protobuf.cmake
+++ b/hailort/cmake/external/protobuf.cmake
@@ -41,7 +41,9 @@
if(WIN32)
set(PROTOBUF_CONFIG_DIR /usr/src/hailort/hailort/external/protobuf-install/cmake)
-
else() -
set(PROTOBUF_CONFIG_DIR /usr/src/hailort/hailort/external/protobuf-install/lib/cmake/protobuf)
-
elseif(EXISTS /usr/src/hailort/hailort/external/protobuf-install/lib64/cmake/protobuf) -
set(PROTOBUF_CONFIG_DIR /usr/src/hailort/hailort/external/protobuf-install/lib64/cmake/protobuf) -
else() -
set(PROTOBUF_CONFIG_DIR /usr/src/hailort/hailort/external/protobuf-install/lib/cmake/protobuf)
endif()
Files modified:
hailort/cmake/external/protobuf.cmake (patched via build script)
_HAILO.SlackBuild/patch/hailort-protobuf-cmake-aarch64-lib64.patch
_HAILO.SlackBuild/build-hailort-source.sh (patch application added)
ISSUE 003 - HAILO_BUILD_TOOLS=ON references non-existent directory
Date : 2026-04-26
Status : RESOLVED - flag set to OFF
Severity: MEDIUM - configuration failure
Description:
Initial cmake configure used -DHAILO_BUILD_TOOLS=ON assuming this built
hailortcli. It does not. It references an internal ātoolsā subdirectory
that is not included in the public HailoRT release:
CMake Error at hailort/CMakeLists.txt:119 (add_subdirectory):
add_subdirectory given source "tools" which is not an existing directory.
hailortcli is actually built unconditionally via add_subdirectory(hailortcli)
at line 109 of hailort/CMakeLists.txt - no flag required.
Resolution:
Set -DHAILO_BUILD_TOOLS=OFF in cmake configure command.
hailortcli is still built automatically regardless of this flag.
Files modified:
_HAILO.SlackBuild/build-hailort-source.sh
CMAKE CONFIGURE FLAGS - RATIONALE
Flag Value Logic
-DCMAKE_BUILD_TYPE Release Production build, optimised
-DHAILO_BUILD_TOOLS OFF Internal tools dir not in public release
hailortcli is built unconditionally
-DHAILO_BUILD_GSTREAMER OFF GStreamer dev libs not in build env
-DHAILO_BUILD_EXAMPLES OFF Not needed for runtime
-DHAILO_BUILD_UT OFF No unit tests in production build
-DHAILO_BUILD_GENAI_SERVER OFF Not required at this stage
-DHAILO_BUILD_HAILORT_SERVER OFF Not required at this stage
-DCMAKE_INSTALL_PREFIX /usr Slackware standard install prefix
Note: hailortcli IS built - it is unconditional in hailort/CMakeLists.txt.
Note: HAILO_BUILD_GENAI_SERVER and HAILO_BUILD_HAILORT_SERVER can be enabled
in future builds once the core runtime is stable.
ISSUE 004 - del_timer_sync() removed in Linux 6.15+
Date : 2026-04-26
Status : RESOLVED via patch
Severity: CRITICAL - terminal error
Description:
linux/vdma/monitor.c:53 calls del_timer_sync() which was removed in
Linux 6.15 and replaced by timer_delete_sync(). Build fails with:
../vdma/monitor.c:53:5: error: implicit declaration of function
'del_timer_sync' [-Wimplicit-function-declaration]
Kernel 6.18.26 is affected. This will affect all builds on kernel 6.15
and above.
Resolution:
Replace del_timer_sync() with timer_delete_sync() in monitor.c:53.
Patch file:
_HAILO.SlackBuild/patch/hailort-drivers-del-timer-sync-kernel-6.15.patch
Patch applied automatically in build-hailort-drivers-source.sh before
the driver build. Uses --forward flag so it is safely skipped if already
applied.
Patch diff:
ā a/linux/vdma/monitor.c
+++ b/linux/vdma/monitor.c
@@ -50,5 +50,5 @@
void hailo_vdma_monitor_stop(struct hailo_vdma_monitor *monitor)
{
- del_timer_sync(&monitor->timer);
- timer_delete_sync(&monitor->timer);
}
Files modified:
linux/vdma/monitor.c (patched via build script)
_HAILO.SlackBuild/patch/hailort-drivers-del-timer-sync-kernel-6.15.patch
_HAILO.SlackBuild/build-hailort-drivers-source.sh (patch application added)
ISSUE 005 - hailo1x_pci MSI FAILURE THROUGH ASMedia PCIe SWITCH
Date : 2026-05-05
Status : RESOLVED via device tree overlay
Severity: CRITICAL - device not detected
Description:
After installing the HailoRT packages and rebooting, hailortcli scan
reported āHailo devices not foundā. dmesg showed the hailo1x_pci driver
probing but failing with:
hailo1x 0001:06:00.0: Failed to enable MSI -28
Error -28 is -ENOSPC ā the kernel could not allocate an MSI vector. The
Hailo-10H sits behind an ASMedia ASM2806 4-port PCIe switch connected to
the BCM2712 PCIe bridge on the Raspberry Pi 5. MSI vector allocation
through the ASMedia switch fails without explicit device tree configuration.
The hailo1x_pci driver calls pci_enable_msi() with no fallback:
// TODO HRT-2253: use new api for enabling msi: (pci_alloc_irq_vectors)
if ((err = pci_enable_msi(board->pdev))) {
hailo_err(board, āFailed to enable MSI %d\nā, err);
Hailo acknowledge this in TODO HRT-2253.
Resolution:
Add the following to /boot/config.txt under [pi5]:
dtparam=nvme
dtoverlay=pciex1-compat-pi5,no-mip
dtparam=nvme enables the PCIe interface on the Raspberry Pi 5.
dtoverlay=pciex1-compat-pi5,no-mip enables MSI through PCIe switches
on the Raspberry Pi 5.
These lines are included in config.txt.new produced by the
build-boot-firmware-rpi.sh build script.
Files modified:
_HAILO.SlackBuild/config.txt.new - dtparam=nvme and dtoverlay added under [pi5]
HAILO-10H DEVICE FIRMWARE
The Hailo-10H device firmware is not distributed in the HailoRT source tree.
It is a separate binary download hosted on Hailoās AWS S3 bucket.
The hailort-drivers repo includes a reference download script:
hailort-drivers/download_firmware_hailo10h.sh
That script downloads from:
https://hailo-hailort.s3.eu-west-2.amazonaws.com/Hailo10H/5.3.0/FW/hailo10h_fw.tar.gz
It has the HailoRT version hardcoded to 5.3.0.
Our build script (build-hailort-firmware-rpi.sh) uses the same URL pattern
but derives the version dynamically from the HailoRT source at build time by
grepping FIRMWARE_VERSION_MAJOR/MINOR/REVISION from hailort/CMakeLists.txt.
This ensures the firmware version always matches the HailoRT version being
built, regardless of what version is checked out.
The firmware tarball (hailo10h_fw.tar.gz) extracts to a set of binary blobs
which are installed to /lib/firmware/hailo/hailo10h/. The hailo1x_pci driver
requests these files via the kernel firmware loader at device probe time.
The build produces:
hailo-10h-firmware-5.3.0-armv8-1_slackcurrent_06May26_sai.txz
hailo-10h-firmware-5.3.0-armv8-1_slackcurrent_06May26_sai.md5
Installed to:
/lib/firmware/hailo/hailo10h/
PATCHES INDEX
Patch directory (host): /tmp/_HAILO.SlackBuild/patch/
Patch directory (chroot): /tmp/sairpi-chroot/tmp/_HAILO.SlackBuild/patch/
001 hailort-protobuf-cmake-aarch64-lib64.patch
Target : hailort/cmake/external/protobuf.cmake
Fixes : protobuf cmake config path on AArch64 (lib64 vs lib)
Applied: build-hailort-source.sh (automatic, before cmake configure)
Status : Active - awaiting upstream fix from Hailo
002 hailort-drivers-del-timer-sync-kernel-6.15.patch
Target : linux/vdma/monitor.c
Fixes : del_timer_sync() removed in Linux 6.15+, replaced by timer_delete_sync()
Applied: build-hailort-drivers-source.sh (automatic, before driver build)
Status : Active - awaiting upstream fix from Hailo
BUILD ENVIRONMENT
Host OS : Slackware AArch64 current
Host Hardware : Raspberry Pi 5
Chroot : /tmp/sairpi-chroot
cmake (legacy) : 3.31.12 (/usr/local/cmake-3.31/bin/cmake)
cmake (system) : 4.3.2 (/usr/bin/cmake) - NOT used for HailoRT
gcc : 15.2.0
Kernel built : 6.18.26-v8-sairpi5_64
HailoRT version : 5.3.0
protobuf version : 21.12 (v3.21.12, built from source via FetchContent)
BUILD RESULTS
HailoRT v5.3.0 built and installed successfully on 2026-05-06.
Installed:
/usr/lib64/libhailort.so.5.3.0
/usr/lib64/libhailort.so
/usr/lib64/libhailopp.so.1.0.0
/usr/lib64/libhailopp.so.1
/usr/lib64/libhailopp.so
/usr/lib64/cmake/HailoRT/
/usr/lib64/cmake/HailoPP/
/usr/include/hailo/
/usr/bin/hailortcli
Build time: not recorded on this run - to be added on subsequent builds.
HailoRT drivers v5.3.0 built and installed successfully on 2026-05-06.
Installed:
/lib/modules/6.18.26-v8-sairpi5_64/kernel/drivers/misc/hailo1x_pci.ko.xz
/lib/modules/6.18.26-v8-sairpi5_64/kernel/drivers/misc/hailo_integrated_nnc.ko.xz
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DEVELOPMENT STATUS
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This work is ongoing. The SAIRPi build system, packages, documentation and
test procedures described in this document are all under active development.
Results, findings and fixes will be updated as development progresses.
These build scripts and files WILL change. In order to get results and a working
environment we have had to navigate uncharted territory and cross many borders
that never before existed. For development purposes of this first-of-its-kind work
itās messy right now but the important thing is that itās working as expected.
Rest assured that before any build scripts are released publicly we will revise
and clean-up the process dramatically.
Hailo Technologies are advised that all issues and findings documented here are
reported āas isā and they are confirmed and verified.
SAIRPi Project - sairpi.project@penthux.net
