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This section explains how to resolve common Yocto build failures and debug issues in the Qualcomm Linux workspace.

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Debug tools

packagegroup-core-tools-debug defined in the <workspace>/layers/poky/meta directory adds debug tools as part of rootfs. The <workspace>/layers/meta-qcom-hwe/recipes-devtools directory contains the appended package group recipe as packagegroup-core-tools-debug.bbappend. This append file adds ltrace, perf, sysstat, and valgrind tools to this package group. For more information, see Debug Linux user space issues.

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Common Yocto build failures

For common build failures related to QA issues such as version going backwards, see Verify QA issue: Version going backwards.

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Layer exclusion issues

If BitBake didn’t parse a newly added layer, the recipes from that layer aren’t included in the image.
  1. Run the following command, and verify that you see the layer in the output: 
    bitbake -e | grep ^BBLAYERS=
  2. If you can’t find the layer, confirm the contents of the conf/bblayers.conf file to ensure that the layer is included.

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Debug builds

To generate a debug build, run the following command: 
kas shell meta-qcom/ci/<machine-name>.yml:meta-qcom/ci/<distro-name>.yml:meta-qcom/ci/debug.yml
bitbake qcom-multimedia-image
To understand which kernel defconfig and config fragments are used when DEBUG_BUILD is set to 1, see Kernel recipe, under Kernel recipes. The following code snippet from recipes-kernel/linux/linux-qcom_6.18.bb enables the debug configuration fragment for the kernel being built: 
KBUILD_CONFIG_EXTRA:append = " ${@oe.utils.vartrue('DEBUG_BUILD', '${S}/kernel/configs/debug.config', '', d)}"
For a dedicated debug build guide, see Create a build for debugging.

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Tooling & logs

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Verify QDL and ModemManager

If you are using a Linux distribution with systemd, use the systemctl command to stop ModemManager. The following is an example from Ubuntu 22.04:
  1. To verify the ModemManager status, run the following command: 
    systemctl status ModemManager

    ModemManager.service - Modem Manager
Loaded: loaded (/lib/systemd/system/ModemManager.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2023-11-28 16:28:15 IST; 3 months 4 days ago
Main PID: 1338 (ModemManager)
Tasks: 3 (limit: 4915)
CGroup: /system.slice/ModemManager.service
        └─1338 /usr/sbin/ModemManager --filter-policy=strict

    ps aux | grep -i modemmanager

    root      1338  0.0  0.0 434332  9544 ?        Ssl   2023  10:39 /usr/sbin/ModemManager --filter-policy=strict
  2. To stop ModemManager, run the following command: 
    systemctl stop ModemManager
systemctl status ModemManager

    ModemManager.service - Modem Manager
Loaded: loaded (/lib/systemd/system/ModemManager.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Sun 2024-03-03 20:08:32 IST; 4s ago
Process: 1338 ExecStart=/usr/sbin/ModemManager --filter-policy=strict (code=exited, status=0/SUCCESS)
Main PID: 1338 (code=exited, status=0/SUCCESS)
  3. The ps aux command doesn’t show any entry for /usr/sbin/ModemManager. If you need ModemManager, you must restart it after the flashing is complete and verify if it has started: 
    systemctl start ModemManager
systemctl status ModemManager

    ModemManager.service - Modem Manager
Loaded: loaded (/lib/systemd/system/ModemManager.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2024-03-03 20:11:46 IST; 43s ago
Main PID: 14785 (ModemManager)
Tasks: 3 (limit: 4915)
CGroup: /system.slice/ModemManager.service
        └─14785 /usr/sbin/ModemManager --filter-policy=strict

    ps aux | grep -i modemmanager

    root     14785  4.6  0.0 434332  9160 ?        Ssl  20:11   0:00 /usr/sbin/ModemManager --filter-policy=strict