c - 无法链接linux内核模块:警告:“snd_device_new”未定义

Question

我正在学习Linux内核驱动程序，试图为ADC实现SPI声音驱动程序。
该代码可能无法正常工作，但可以编译。
链接出现第一个问题，报告以下错误：

WARNING: "snd_pcm_lib_ioctl" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_device_new" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_pcm_lib_preallocate_pages_for_all" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_pcm_set_ops" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_pcm_new" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_card_register" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_card_create" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_pcm_hw_constraint_integer" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_pcm_lib_malloc_pages" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_pcm_lib_free_pages" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!
WARNING: "snd_card_free" [/home/pi/rpi/gpio/module/spi-mcp3002.ko] undefined!

源代码是 https://github.com/mpromonet/rpi/blob/master/gpio/module/spi-mcp3002.c，makefile是 https://github.com/mpromonet/rpi/blob/master/gpio/module/Makefile。

我猜没有设置一些内核选项，但是哪个？

我尝试使用zcat /proc/config.gz查找禁用的选项。 grep SND | grep“ ^＃”

# CONFIG_SND_DYNAMIC_MINORS is not set
# CONFIG_SND_VERBOSE_PRINTK is not set
# CONFIG_SND_DEBUG is not set
# CONFIG_SND_OPL3_LIB_SEQ is not set
# CONFIG_SND_OPL4_LIB_SEQ is not set
# CONFIG_SND_SBAWE_SEQ is not set
# CONFIG_SND_EMU10K1_SEQ is not set
# CONFIG_SND_AC97_POWER_SAVE is not set
# CONFIG_SND_ARMAACI is not set
# CONFIG_SND_ATMEL_SOC is not set
# CONFIG_SND_DESIGNWARE_I2S is not set
# CONFIG_SND_SOC_ALL_CODECS is not set
# CONFIG_SND_SIMPLE_CARD is not set

我将查看内核源代码，这些符号的定义是由什么造成的……但是，如果有人知道我也许可以保存一些内核构建：）

Answer 1

在内核本身之前构建模块，我可能会出错。符号不在Module.symvers中

重新执行模块安装和重新启动解决了问题：

make 
make module_install
reboot