smi2021 kernel module causes panic

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Plug in the Somagic USB device, it shows up properly in dmesg:

[    6.488608] usb 2-1: New USB device found, idVendor=1c88, idProduct=003c
[    6.488613] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    6.488615] usb 2-1: Product: SMI Grabber DEV 
[    6.488617] usb 2-1: Manufacturer:  Somagic, Inc.  
[    6.488619] usb 2-1: SerialNumber: SMIGRABBER9876543210
[    6.542011] bcma-pci-bridge 0000:07:00.0: no hotplug settings from platform
[    6.604178] saa7115 7-004a: gm7113c found @ 0x94 (smi2021)
[    6.611733] 8:3:1: cannot get freq at ep 0x84
[    6.621221] usb_audio: Warning! Unlikely big volume range (=3328), cval->res 
is probably wrong.
[    6.621226] usb_audio: [2] FU [Mic Capture Volume] ch = 1, val = 
4608/7936/1<6>
[    6.621485] usbcore: registered new interface driver snd-usb-audio
[    6.630083] smi2021 2-1:1.0: Somagic Easy-Cap Video Grabber

2. Run VLC
3. Select Media -> Open Capture Device
4. Choose video device, here /dev/video1, and click play (Video playback starts)
5. Select again Media -> Open Capture Device
6. Choose some random audio device and click play

This will trigger the panic. Always. It's easily reproducible for me.

I downloaded and built the smi2021 module just today according to the 
"BuildingKernelModule" section in your wiki. I built a whole kernel from source 
on my Ubuntu 14.04 and installed the debs.

Screenshot of the panic is attached. Sorry for the bad quality, taken with a 
budget phone :)

Original issue reported on code.google.com by mvey...@gmail.com on 25 Nov 2014 at 5:58

Attachments:

• IMG_20141125_183119.jpg
• IMG_20141125_183149.jpg

[GoogleCodeExporter]

Same behaviour seen here.

Kernel 3.19.3

Using Arch Linux, building from Aur and Git.

Original comment by dangray...@gmail.com on 25 Apr 2015 at 7:07