# [SOLVED] Gentoo is unable to detect my DVD drive...

## Bob Leny

I put a DVD in the DVD drive for the first time the other day and it didn't mount.

I tried to mount it manually with the following command:

```
# mount -o loop /dev/cdrom
```

I get this error message:

```
mount: can't find /dev/cdrom in /etc/fstab or /etc/mtab
```

I checked fstab, where I found this line:

```
/dev/cdrom /mnt/cdrom auto noauto,user 0 0
```

Then I checked /dev to see if cdrom is there, it's not:

http://pastebin.com/7JYTETLd

As far as I know none of those devices are for the DVD drive.

I'm really not sure what else I should do...

What should I do, almighty Gentoo users!?

Thanks!Last edited by Bob Leny on Tue Nov 30, 2010 9:30 pm; edited 1 time in total

----------

## NeddySeagoon

Bob Leny,

You have a bit missing from your kernel, maybe two bits.  Post your lspci, so we can see your hardware and start at the beginning.

It might be useful to know if your DVD is a PATA or SATA device but we will cover all the bases so if you don't know, it probably won't matter.

----------

## Bob Leny

My lspci can be found here:

http://pastebin.com/Z2cuw9tY

I don't see it listed though.

My DVD drive is a Pioneer CD/DVD SATA combo drive and I have only one optical drive in my system.

I would not be surprised if I am missing a couple of things in my kernel...

----------

## NeddySeagoon

Bob Leny,

lspci, lists the hardware on PCI buses on your motherboard. Your DVD will be attached to one of them. Possibilities are 

```
00:11.0 SATA controller: ATI Technologies Inc SB700/SB800 SATA Controller [IDE mode]

00:14.1 IDE interface: ATI Technologies Inc SB700/SB800 IDE Controller
```

In the passing, you should not use your SATA controller in [IDE mode]. That is intended to allow Windows XP users to install the AHCI driver.

Linux users should use AHCI mode. Fix that in your BIOS.  Firstly, IDE mode is normally much slower that AHCI mode. Secondly, not all the SATA ports work in IDE mode. If your DVD were connected to one of the disabled ports - it wouldn't work.

As you can boot, we can be fairly confident that your SATA drive works, so there are two things to check in the kernel.

```
<*> SCSI CDROM support 
```

as all CDROMS are now SCSI, even PATA ones.

and ...

```
  [*]   ATA SFF support

  [*]     ATA BMDMA support

  <*>       ATI PATA support
```

Thats two menu items inside <*> Serial ATA and Parallel ATA drivers  ---> and the chip set driver  for your PATA chip set, in case your CDROM is a PATA device.

While you are there    < > ATA/ATAPI/MFM/RLL support (DEPRECATED)  --->  must be off, as you don't want two drivers for the same hardware.

Your real CDROM will be /dev/sr0 but udev will make all the usual symlinks pointing to it.

One last tidy up, if your device appears with the wrong number, delete  /etc/udev/rules.d/70-persistent-cd.rules and reboot. That file will be recreated.

----------

## Bob Leny

I tri-boot between windows vista, Kubuntu, and Gentoo. So, I know the DVD drive works. I also know it is a SATA drive as I'm the one who built my computer.

"SCSI CDROM support" was already enabled.

"ATA SFF support" was also already enabled.

I can't find "ATA BMDMA support". It should be in the same list as the "ATA SFF support", right? Where else could this option be located?

"ATA/ATAPI/MFM/RLL support (DEPRECATED) --->" was not enabled.

"ATI PATA support" was not enabled, but I know for a fact that my DVD drive is connected through SATA. In fact, the only IDE controller on the board has nothing plugged into it. Do I still need to enable this option?

I don't know why my SATA controller would be IDE mode, but I will look in my giant BIOS to see if I can't figure out how to change it to AHCI mode.

Could a combination of my SATA controller being in IDE mode and a lack of "ATA BMDMA support" be the reason why my DVD drive doesn't work?

----------

## Bob Leny

I did figure out how to set my SATA controller to AHCI mode. Of course now, vista crashes during start up, lol...

I have also made a screen shot of all the options available to me in the "Serial ATA and Parallel ATA drivers" menu:

http://img88.imageshack.us/img88/4603/map3q.png

----------

## Bob Leny

Hmm, apparently, changing my BIOS setting did the trick, because I just noticed that sr0 and cdrom are in /dev/

I just tried to mount my DVD drive, I get this error:

```
# mount /dev/sr0 /media/cdrom/

mount: unknown filesystem type 'udf'
```

Does that mean I need to enable UDF support?

Where would that option be located in the kernel?

This seems to mount the DVD drive just fine:

```
mount -t iso9660 /dev/cdrom /mnt/cdrom/
```

Now it won't unmount, lol...

----------

## NeddySeagoon

Bob Leny,

ATA BMDMA support is a recent tidy up added to the kernel menu system - if you don't have it, thats fine.

You do not need ATI PATA support - yet

 *Quote:*   

> SATA controller to AHCI mode. Of course now, vista crashes ... 

 Does vista have an AHCI driver ?

XP does not, well only as an extra, - hence the IDE mode, so you can install the AHCI driver. 

DVDs usually have two ToC ... one in UDF and one in ISO9960, either work but as optical storage gets bigger, ISO9960 won't work.

It breaks gently at 4G.  You can have files but not dirs beyond 4G, I think the max filesize is 2G too.

UDF is under Filesystems in the kernel.

If you want to use DVD+RW as big floppies, you need UDF too, although, in theory you can use any filesystem.

The right thing to do is to stick with AHCI and fix Visa.

----------

## Bob Leny

 *NeddySeagoon wrote:*   

> The right thing to do is to stick with AHCI and fix Visa.

 

I'm not really sure it's possible to fix Vista, but I can probably figure out how to install AHCI drivers...

I did get UDF filesystem support enabled and it works great now!

Maybe you can help me get the cdrom to auto mount?

This is the related line in fstab:

```
/dev/cdrom              /mnt/cdrom      auto            noauto,user             0 0
```

I've tried commenting that line out and changing "noauto" to "auto" with no success.

Isn't fstab just for when your booting anyways, which means unless there is a CD in the drive at start up, it won't mount the CD?

I started looking at this guide here:

http://www.gentoo-wiki.info/Autofs

but I thought the auto mounting process was a lot simpler.

Should I follow that guide?

I do have "Kernel automounter version 4 support" already enabled, which think is necessary in order to mount and run Gentoo...

Also, is there any advantage or disadvantage to installing parts or the kernel as a module?

----------

## NeddySeagoon

Bob Leny,

/etc/fstab is nothing to do with auto mounting.

In fact, if your cdrom is listed there, auto mounting won't work.

There are several methods of automounting and I don't use any of them.

Automounting kills DVD+RW media that you have set up to use read/write, as the media is only good for 1000 writes or so.

Automounting costs a write every mount, so its a bad thing to me.

----------

## Bob Leny

Oh, that's fine, I don't really care if I have to manually mount it or not. It is a nice feature though...

Thank you for your help!

----------

