At Fri, 12 Jun 2015 02:28:16 -0400, Azizul Hakim wrote:
Hi,
I've been developing a sound card driver for a USB device using ALSA. My driver is almost working but I've got one small issue. If I try to unload the driver module using "rmmod" command when the device is still connected to the USB port, it says "Module is in use" even though I'm not playing any sound files or anything.
If I try to execute the "lsmod" command I see that it is saying the usage count of my driver to be 1, but it doesn't say anything about who is using it. Once I disconnect the device from the USB port, I can easily unload the module.
So it seems to me it won't be possible to unload a sound card driver if the card is attached in the computer. Is my assumption correct? If not, what might be some key points to solve the issue?
Check "fuser -v /dev/snd/*" as root. Something (e.g. a mixer application or sound backend) must be accessing the device.
Takashi