sr0 doesn't exist.

Noone_ · 10-07-2022, 04:16 PM

Hello,
I am using Debian 11.5 O.S. My DVD was working fine until last week. Attached is a snapshot of what I was doing to fix the problem. As you have seen in the attached file, sr0 now is invalid blocked device. However, when I reboot the system, I will see the message:"sr0 doesn't exist" again if I try to mount it. Please help.
Thank you very much.

Best regards,

Arnulf · 10-07-2022, 06:17 PM

Standard procedure:

Unplug (power cord and SATA or PATA cable) problematic DVD drive
Check unplugged cables for visual damages
Replug (power cord and SATA or PATA cable) problematic DVD drive
Try again accessing to /dev/sr0: Success = Stop here
Replace SATA or PATA cable with a well-known working cable
Try again accessing to /dev/sr0: Success = Stop here
Try problematic DVD drive in another computer
Try a well-known working DVD drive in this computer
…

If you want more help please give manufacturers and models of problematic DVD drive and mainboard on that it's connected.

michaelk · 10-07-2022, 06:27 PM

In addition just to cover all bases make sure the SATA channel or PATA controller connected to the DVD drive is still enabled in the BIOS/UEFI.

Check the output of the dmesg and look for error messages related to the DVD drive.

dmesg | grep CD-ROM
dmesg | grep sr0

computersavvy · 10-07-2022, 07:07 PM

There are always 3 things (minimum) to check when a device seems to fail.
1. Cables, both power and signal, between the mobo and the device. Connections at both ends properly seated, possible damage to the cable and connectors. Loss of power or loss of signal are the most common problems.
2. The device itself. Did something happen to cause failure? do signal lights (if any) work? does the tray open & close? Try the device in a different machine or try a different device in this machine.
3. Connections at the PSU and the MOBO. Did something disable the port on the mobo? maybe in bios?
4. A fourth thing to check, and least intrusive, is to look at the logs and see what they might tell you. dmesg is able to give you info about all devices it configures or fails to configure during boot. Missing a device might show up as total absence or failed config.

Steps outlined above cover most of this, but users should remain aware of potential causes and be able to investigate.

Emerson · 10-07-2022, 07:17 PM

While all above if good advice in real life a disappearing device often means a failed device. I would try with some thumbdrive Linux to make sure it is not my installed Linux at fault.

mrmazda · 10-07-2022, 08:45 PM

As a general rule, DVD drives made in recent years are cheap, and thus, unreliable long-term. If you have an old one, treasure it.

!!! · 10-07-2022, 10:08 PM

It might end up as sr1 (or more rarely: even something more obscure)
https://www.linuxquestions.org/quest...dvd-0-a-581025

I love lsblk (and inxi lspci dmidecode)
https://www.cyberciti.biz/faq/linux-...lu-ray-device/
https://neverendingsecurity.wordpres...015/03/14/932/

Here's a way to post output without having to take a picture:

Code:

(lsblk -f; ls -l /dev/sr*) | nc termbin.com 9999

Also look into the script command. (Then nc < typescript)

Maybe easier: right clicking on an xterm window usually gives you a copy (the selected=highlighted text) option, so you can paste into your web browser (LQ in code tags PLEASE)

Noone_ · 10-10-2022, 03:42 AM

Quote:

Originally Posted by Arnulf

Standard procedure:

Unplug (power cord and SATA or PATA cable) problematic DVD drive
Check unplugged cables for visual damages
Replug (power cord and SATA or PATA cable) problematic DVD drive
Try again accessing to /dev/sr0: Success = Stop here
Replace SATA or PATA cable with a well-known working cable
Try again accessing to /dev/sr0: Success = Stop here
Try problematic DVD drive in another computer
Try a well-known working DVD drive in this computer
…

If you want more help please give manufacturers and models of problematic DVD drive and mainboard on that it's connected.

Thanks . It works with window O.S. and Debian 11 as well. It just happened recently with Debian (not recognize the DVD or sr0). Attached is a snapshot of Devices Manager of windows O.S.

pan64 · 10-10-2022, 03:48 AM

probably it has a different name now, not sr0. Probably something went wrong during the boot. Probably a kernel driver is missing. It is working on windows, therefore it is not a hardware error. But all the other steps should be checked (log files, dmesg, /dev, lsblk ....).

Noone_ · 10-11-2022, 11:02 PM

Quote:

Originally Posted by pan64

probably it has a different name now, not sr0. Probably something went wrong during the boot. Probably a kernel driver is missing. It is working on windows, therefore it is not a hardware error. But all the other steps should be checked (log files, dmesg, /dev, lsblk ....).

Thanks for your advices, I have tried to look at .config file, but no luck. Now, I am using the external usb dvd which is very easy to use, almost no setup needed.

Code:

loc@debian:~$ ls -l /dev/cdrom
lrwxrwxrwx 1 root root 3 Oct 11 15:10 /dev/cdrom -> sr0
loc@debian:~$

!!! · 10-11-2022, 11:18 PM

When you added the external USB CD ROM maybe that became sr0, pushing the internal one to sr1

You only like looking at that one symlink, but none of these other commands?
https://www.cyberciti.biz/faq/linux-...lu-ray-device/

You can 'close' this, by marking it as [SOLVED], if you want.

michaelk · 10-12-2022, 09:47 AM

Look at the output of the lsmod command to see if sr_mod and sg modules are loading.

rnturn · 10-12-2022, 11:04 AM

Quote:

Originally Posted by Noone_

Hello,
I am using Debian 11.5 O.S. My DVD was working fine until last week. Attached is a snapshot of what I was doing to fix the problem. As you have seen in the attached file, sr0 now is invalid blocked device. However, when I reboot the system, I will see the message:"sr0 doesn't exist" again if I try to mount it.

Do the system logs indicate that the device was detected during bootstrap? In my boot.msg file, I see:

Code:

.
.
.
<5>[    8.736747] sd 7:0:3:0: [sdb] Attached SCSI disk
<5>[    8.767912] sd 7:0:4:0: [sdc] Attached SCSI disk
<6>[    8.803233] sr 0:0:0:0: [sr0] scsi3-mmc drive: 48x/48x writer cd/rw xa/form2 cdda tray
<6>[    8.803235] cdrom: Uniform CD-ROM driver Revision: 3.20
<7>[    8.827037] sr 0:0:0:0: Attached scsi CD-ROM sr0
.
.
.

You will likely see something different, obviously, but if you're not seeing anything "sr"-related the first thing I'd check is cabling (power and data).

HTH...

rnturn · 10-12-2022, 11:15 AM

Quote:

Originally Posted by !!!

When you added the external USB CD ROM maybe that became sr0, pushing the internal one to sr1

If the external drive works and you can mount the disc, the "mount" command should confirm which "sr" device was mounted. As you note, it might not be what you'd expect when the USB device is present.

Linux device naming can be a little confusing at times. As new drives have been added to my system, my boot device is now /dev/sdp. [scratches head]