Is the LibreDrive firmware causing Linux to be unable to read DVDs, but still read BluRays just fine?

[MrPenguin]

I do have a file in there called 99-optical-permissions.rules, which I added yesterday in an attempt to fix this issue. The /dev/sr* devices were owned by root:root not root:cdrom so I kept getting permission errors trying to access them.

OK, but I would have expected you to have those rules already in your /usr/lib/udev/rules.d/50-udev-default.rules file, which is part of the

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systemd-udev-258.7-1.fc43.x86_64

package. My own /etc/udev/rules.d/70-persistent-cd.rules file contains rules like these:

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SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_BD}=="1", SYMLINK+="bluray%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_DVD}=="1", SYMLINK+="dvd%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_DVD_RW}=="1", SYMLINK+="dvdrw%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_CD_RW}=="1", SYMLINK+="cdrw%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM}=="1", SYMLINK+="cdrom%n", ENV{GENERATED}="1"

[Laurence5905]

I tried running MakeMKV while the disk was ejected and nothing was in the drive. It sees the drive, it sees that the drive is ejected, no problem. I close the tray with a DVD in the tray and the icon spins -- and then it actually showed the name of the movie on the disc!! That's the first time that's ever happened on this machine with a DVD.

However, when I click the DVD icon to go to the next step, it says "Failed to open disc." And it doesn't give me any reason at all...

I try ejecting the disc and it says "Unmounting, please wait" and then locks up. I have to kill the pid to make it end.

Do all of the above with a BluRay instead of a DVD, and it all works perfectly normally.

[MrPenguin]

However, when I click the DVD icon to go to the next step, it says "Failed to open disc." And it doesn't give me any reason at all...

I try ejecting the disc and it says "Unmounting, please wait" and then locks up. I have to kill the pid to make it end.

Do you have "/dev/dvd" and /"dev/cdrom" symlinks, and do they switch between /dev/sr0, /dev/sr1 and /dev/sr2? I am wondering whether your systemd may be misconfigured, and be switching symlinks around behind your back.

[Laurence5905]

OK, but I would have expected you to have those rules already in your /usr/lib/udev/rules.d/50-udev-default.rules file, which is part of the

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systemd-udev-258.7-1.fc43.x86_64

package.

Weird... My /etc/udev/rules.d/ folder is completely empty now that I removed that 99-optical-permissions.rule file...

My own /etc/udev/rules.d/70-persistent-cd.rules file contains rules like these:

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SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_BD}=="1", SYMLINK+="bluray%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_DVD}=="1", SYMLINK+="dvd%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_DVD_RW}=="1", SYMLINK+="dvdrw%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM_CD_RW}=="1", SYMLINK+="cdrw%n", ENV{GENERATED}="1"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", ENV{ID_CDROM}=="1", SYMLINK+="cdrom%n", ENV{GENERATED}="1"

I just created that file with those contents... Do you have any other files that might be necessary? I looked in /lib/udev/rules.d and only found one file that might be pertinent -- 60-cdrom_id.rules. But it didn't have any of that stuff in it. So I just added your 70-persistent-cd.rules file to my /etc/udev/rules.d/ folder. Rebooting...

[Laurence5905]

I just checked, and now I do have /dev/dvd0 and /dev/cdrom0 and /dev/bluray0 symlinks...

And it seems to have changed nothing.

[MrPenguin]

Weird... My /etc/udev/rules.d/ folder is completely empty now that I removed that 99-optical-permissions.rule file...

The system's default rules are in the /usr/lib/udev/rules.d/ directory, including these:

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SUBSYSTEM=="block", GROUP="disk"
SUBSYSTEM=="block", KERNEL=="sr[0-9]*", GROUP="cdrom"

I just created that file with those contents... Do you have any other files that might be necessary? I looked in /lib/udev/rules.d and only found one file that might be pertinent -- 60-cdrom_id.rules. But it didn't have any of that stuff in it. So I just added your 70-persistent-cd.rules file to my /etc/udev/rules.d/ folder. Rebooting...

Those new rules just add appropriate symlinks for optical devices. But you shouldn't have needed to add your own 99-optical-permissions.rule file in the first place, because the default rules should have handled that already. This suggests you may have a deeper configuration problem.

[Laurence5905]

This suggests you may have a deeper configuration problem.

I went and dug out my old Apple SuperDrive. It's DVD only, not BluRay, but if there's a system-wide misconfiguration, this drive should fail to read also.

After dealing with the well-known "Apple SuperDrive won't unlock unless you plug it into a Mac" bug, I can insert a DVD, the system recognizes it, and MakeMKV will scan it no problem. Just for kicks, I ripped one of the smaller titles on this DVD, and it worked perfectly.

So that would seem to confirm 100% that it is the LG drive itself that's incompatible with Linux. Possibly due to the LibreDrive firmware...

Will I brick my drive by flashing new firmware to it? The firmware located here: viewtopic.php?f=16&t=19634

[MrPenguin]

So that would seem to confirm 100% that it is the LG drive itself that's incompatible with Linux. Possibly due to the LibreDrive firmware...

Will I brick my drive by flashing new firmware to it? The firmware located here: viewtopic.php?f=16&t=19634

I cannot help you with LG firmware, because I simply don't know. However, I can say that the default udev rules in /usr/lib/udev/rules.d should add your SCSI disks to the "disk" group, and your SCSI optical drives to the "cdrom" group. So as long as your user belongs to both of these groups (see your /etc/group file) then you shouldn't need a 99-optical-permissions.rule file.

[Laurence5905]

I cannot help you with LG firmware, because I simply don't know. However, I can say that the default udev rules in /usr/lib/udev/rules.d should add your SCSI disks to the "disk" group, and your SCSI optical drives to the "cdrom" group. So as long as your user belongs to both of these groups (see your /etc/group file) then you shouldn't need a 99-optical-permissions.rule file.

Yep. That file is gone now. I do have the 70-persistent-cd.rules file that you gave me, and I had to add a 50-apple-superdrive.rules file to get past the "unlock" bug on the SuperDrive, but other than that, there aren't any files in my /etc/udev/rules.d folder any more.

[georgesgiralt]

Hello
The switch between /dev/sr1 and /dev/sr2 is due to the drive hard resetting itself on error.
When he does that, the host loose connection with the drive. So see a new drive when the drives connect back after the reset. But the old sr node has not been closed properly so remains. Hence, the host allocate a new node to the "new" drive...
If you look closely, you'll find that the USB port address has changed too (because of the hard reset of the drive).
It has been a very long time I used a Fedora platform, so I can't comment on the optical disk behavior, sorry.
Just my 2¢

[MrPenguin]

I just checked, and now I do have /dev/dvd0 and /dev/cdrom0 and /dev/bluray0 symlinks...

And it seems to have changed nothing.

I wouldn't have expected those rules to change anything by themselves. My concern was more that you had (e.g.) a "/dev/bluray" or "/dev/cdrom" symlink which was being silently switched from "/dev/sr1" to "/dev/sr2", and that an application was configured always to use "/dev/bluray" etc. Telling systemd to create explicit links would allow you to configure your applications more precisely.

[science-nerd]

Seems quite hard to pinpoint the cause.

How about eliminating all current variables and installing fresh makemkv from a USB live session of let's say an Arch distro like CachyOS and then try to see if the issue can be replicated, without touching your current system? (by default the sg kernel module is not loaded, modprobe will be needed).

Makemkv is in the AUR (Arch User Repository), you will need either yay or paru pacman wrappers to access it