Kernel modules not loaded during boot

Question

Observing that some kernel modules are not being loaded in the latest kernel 5.15.34-v7.

So I have built a core-image-base from meta-raspberrypi (0135a02) and while trying access the camera using Picamera got some errors. The errors mainly complain about mmal drivers not present.

root@raspberrypi3:~# python3
Python 3.10.4 (main, Mar 23 2022, 20:25:24) [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from picamera import PiCamera
>>> camera = PiCamera()
mmal: mmal_vc_shm_init: could not initialize vc shared memory service
mmal: mmal_vc_component_create: failed to initialise shm for 'vc.camera_info' (7:EIO)
mmal: mmal_component_create_core: could not create component 'vc.camera_info' (7)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.10/site-packages/picamera/camera.py", line 408, in __init__
    self._init_revision(options)
  File "/usr/lib/python3.10/site-packages/picamera/camera.py", line 480, in _init_revision
    with mo.MMALCameraInfo() as camera_info:
  File "/usr/lib/python3.10/site-packages/picamera/mmalobj.py", line 2425, in __init__
    super(MMALCameraInfo, self).__init__()
  File "/usr/lib/python3.10/site-packages/picamera/mmalobj.py", line 696, in __init__
    mmal_check(
  File "/usr/lib/python3.10/site-packages/picamera/exc.py", line 184, in mmal_check
    raise PiCameraMMALError(status, prefix)
picamera.exc.PiCameraMMALError: Failed to create MMAL component b'vc.camera_info': I/O error
>>> 
>>> 
root@raspberrypi3:~# 

After digging through my system found an older build (don't know why I didn't delete it but thankfully it gave some insight into the issue), I tried booting that image and everything seems to be working fine.

So I checked out to the commit which the older build was using (63a3d8cb17c5d1affe8f2848f45fcc6a706f9412), and the camera worked fine(though I had to make few changes, which are not significant for this issue). While analyzing the bootlogs found that the latest build (0135a02) doesn't load all the drivers.

Also I have observed that the kernel module are compressed in the 5.15.34 kernel, eg: root@raspberrypi3:~# ls /lib/modules/5.15.34-v7/kernel/drivers/usb/gadget/libcomposite.ko.xz and while trying load the modules using modprobe getting the following error:

root@raspberrypi3:~# ls /lib/modules/5.15.34-v7/kernel/drivers/usb/gadget/legacy/
g_acm_ms.ko.xz        g_cdc.ko.xz           g_hid.ko.xz           g_midi.ko.xz          g_printer.ko.xz       g_webcam.ko.xz        gadgetfs.ko.xz
g_audio.ko.xz         g_ether.ko.xz         g_mass_storage.ko.xz  g_multi.ko.xz         g_serial.ko.xz        g_zero.ko.xz
root@raspberrypi3:~# modprobe gadgetfs
modprobe: FATAL: Module gadgetfs not found in directory /lib/modules/5.15.34-v7

My question is what and where the changes have happened to the kernel between 63a3d8cb17c5d1affe8f2848f45fcc6a706f9412 (5.10) and 0135a02 (5.15) , so that I can look into and adapt the changes required ?

Note: All the commit hashes which are mentioned above are of meta-raspberrypi repo.

Logs

lsmod logs

• 5.15.34

root@raspberrypi3:~# lsmod
Module                  Size  Used by
root@raspberrypi3:~#

• 5.10.81

root@raspberrypi3:~# lsmod
Module                  Size  Used by
rfcomm                 49152  2
cmac                   16384  3
algif_hash             16384  1
nfc                    86016  0
aes_arm_bs             24576  2
crypto_simd            16384  1 aes_arm_bs
cryptd                 24576  2 crypto_simd
algif_skcipher         16384  1
af_alg                 28672  6 algif_hash,algif_skcipher
bnep                   20480  2
hci_uart               40960  1
btbcm                  16384  1 hci_uart
bluetooth             421888  31 hci_uart,bnep,btbcm,rfcomm
ecdh_generic           16384  2 bluetooth
ecc                    36864  1 ecdh_generic
ipv6                  503808  26
brcmfmac              331776  0
brcmutil               24576  1 brcmfmac
sha256_generic         16384  0
bcm2835_v4l2           49152  0
cfg80211              782336  1 brcmfmac
bcm2835_codec          40960  0
bcm2835_isp            32768  0
v4l2_mem2mem           36864  1 bcm2835_codec
rfkill                 32768  4 bluetooth,nfc,cfg80211
bcm2835_mmal_vchiq     36864  3 bcm2835_isp,bcm2835_codec,bcm2835_v4l2
videobuf2_dma_contig    20480  2 bcm2835_isp,bcm2835_codec
videobuf2_vmalloc      16384  1 bcm2835_v4l2
videobuf2_memops       16384  2 videobuf2_dma_contig,videobuf2_vmalloc
videobuf2_v4l2         32768  4 bcm2835_isp,bcm2835_codec,bcm2835_v4l2,v4l2_mem2mem
videobuf2_common       61440  5 bcm2835_isp,bcm2835_codec,bcm2835_v4l2,v4l2_mem2mem,videobuf2_v4l2
raspberrypi_hwmon      16384  0
videodev              253952  6 bcm2835_isp,bcm2835_codec,videobuf2_common,bcm2835_v4l2,v4l2_mem2mem,videobuf2_v4l2
mc                     45056  6 bcm2835_isp,bcm2835_codec,videobuf2_common,videodev,v4l2_mem2mem,videobuf2_v4l2
vc_sm_cma              32768  2 bcm2835_isp,bcm2835_mmal_vchiq
uio_pdrv_genirq        16384  0
uio                    20480  1 uio_pdrv_genirq
fixed                  16384  0
root@raspberrypi3:~# 

Answer 1

Make sure you have kernel-modules installed:

IMAGE_INSTALL_append = " kernel-modules"

EDIT

The package that provides all kernel modules is kernel-modules, or each modules is within a separate package kernel-module-<module_name>. For meta-raspberrypi, they set kernel-modules as a package not essential for boot, means that if the package is not found, the board should boot normal:

• meta-raspberrypi/conf/machine/include/rpi-base.inc

MACHINE_EXTRA_RRECOMMENDS += "kernel-modules udev-rules-rpi"

In previous meta-raspberrypi branches, it was a rpi image recipe rpi-basic-image.bb:

# Base this image on core-image-minimal
include recipes-core/images/core-image-minimal.bb

# Include modules in rootfs
IMAGE_INSTALL += " \
    kernel-modules \
    "

SPLASH = "psplash-raspberrypi"

IMAGE_FEATURES += "ssh-server-dropbear splash"

do_image:prepend() {
    bb.warn("The image 'rpi-basic-image' is deprecated, please use 'core-image-base' instead")
}

So, the only thing needed for integrating the kernel modules is kernel-modules package, either by the image example, or try:

• local.conf

MACHINE_EXTRA_RRECOMMENDS_remove = "kernel-modules"