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raspberrypi / linux

Kernel source tree for Raspberry Pi-provided kernel builds. Issues unrelated to the linux kernel should be posted on the community forum at https://forums.raspberrypi.com/
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unable to use g_cdc/g_ether with gadget boot without initrd #3754

Open H-Sachse opened 4 years ago

H-Sachse commented 4 years ago

Describe the bug usb gadget booting into NFS root fails. can not load g_ether/g_cdc drivers without resorting to initrd, because drivers are modules.

To reproduce gadget boot recent RaspberryPiOS lite

Expected behaviour raspberrypi kernel can be gadget booted with g_ether/g_cdc functionality

Actual behaviour boot stalls with no network connectivity

System raspberrypi zero-w connected via USB to raspberrypi 3B+ current rpiboot from github OS: Stretch updated to Buster 10.4 Kernel 5.4.51-v7+ #1327 SMP Thu Jul 23 10:58:46 BST 2020

Additional context I tried setting up NFS root for a gadget booted RPi-zero, but the boot stalls due to missing gadget modules in the kernel.

ED6E0F17 commented 4 years ago

Yes. You will need kernel modules for USB, or firmware for the wifi, before you can get a network connection to continue the boot process, so you will need an initrd.

H-Sachse commented 4 years ago

Wifi has nothing to do with it, and if you want to do USB gadget boot, needing an initrd is an unnecessary hassle.

the whole of all gadget modules and function for the RPI0/1 kernel is only 224k in size and could be included into the kernel

24K function/u_ether.ko
20K function/u_serial.ko
16K legacy/g_acm_ms.ko
12K legacy/g_audio.ko
12K legacy/g_cdc.ko
16K legacy/g_ether.ko
12K legacy/g_hid.ko
16K legacy/g_mass_storage.ko
12K legacy/g_midi.ko
16K legacy/g_multi.ko
12K legacy/g_printer.ko
12K legacy/g_serial.ko
12K legacy/g_webcam.ko
16K legacy/g_zero.ko
224K    total