# v4l2 in kernel settings

## miraceti

I am upgrading almost a year old Gentoo and I am facing a lot of problems which I have to solve.

I try to compile Linux Kernel v2.6.21-gentoo-r4 but I have problems to set it up. When I do traditional 

```
#cd /usr/src/linux

#make mrproper

#make menuconfig

```

I can go through the settings. However, I did not find how to set up v4l2. In my previous kernel linux-2.6.17-gentoo-r7, the settings for multimedia devices looked quite different. I used to use tvaudio and bttv modules. What I should use nowadays? How can I set it up?

Thanks for any help.

Multimedia Devices menu:

```
<M> Video For Linux

[ ]   Enable Video For Linux API 1 (DEPRECATED)

[*]   Enable Video For Linux API 1 compatible Layer

      Video Capture Adapters  --->

      Radio Adapters  --->

    Digital Video Broadcasting Devices  --->

< > DABUSB driver
```

Video Capture menu:

```
--- Video Capture Adapters

[ ] Enable advanced debug functionality

[*] Autoselect pertinent encoders/decoders and other helper chips

< > Virtual Video Driver

    V4L USB devices  --->

```

When I unselect "Autoselect pertinent...", an option 

```
Encoders/decoders and other helper chips  --->
```

 appears. But if I go into this (Encoders/decoders and...) submenu, I can only see:

```
--- Audio decoders

--- Video decoders

--- Video and audio decoders

--- MPEG video encoders

--- Video encoders

--- Video improvement chips
```

and I cannot select anything!

What's going on here?

lspci says:

```
01:04.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)

01:04.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)
```

Modprobing videodev (I found this in menuconfig help for  the item "Video For Linux":

```
# modprobe -v videodev

insmod /lib/modules/2.6.21-gentoo-r4/kernel/drivers/media/video/videodev.ko

FATAL: Error inserting videodev (/lib/modules/2.6.21-gentoo-r4/kernel/drivers/media/video/videodev.ko): Unknown symbol in module, or unknown parameter (see dmesg)

```

dmesg then says only:

```
videodev: Unknown symbol request_module
```

----------

## PaulBredbury

To fix "unknown symbol", compile the kernel properly.

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## miraceti

Problem was in missing configuration of I2C and chosen "Enable Video For Linux API 1 compatible Layer".

----------

