Linux: MakeMKV 2.0.0 stalls at high CPU with LG BU40N firmware 1.05

[jerwal]

MakeMKV hangs when scanning either a UHD Blu-ray or an ordinary Blu-ray in my LG BU40N. Detection with both optical drives empty completes normally.

System
- Linux Mint 22.3, x86-64
- Kernel: 7.0.0-42-generic
- MakeMKV 2.0.0, locally packaged from the official Linux release
- /dev/sr0: LG BU40N, SATA, firmware 1.05
- Firmware identifier date: 212404231347
- LibreDrive status previously displayed: “Possible, not yet enabled”
- /dev/sr1: LG GGC-H20L, SATA, firmware 1.03

Symptoms and reproduction
With both drives empty, this command detects both drives and exits within five seconds:

Code: Select all

makemkvcon -r info disc:9999

With an ordinary, non-4K John Wick Blu-ray in the BU40N, this command prints only the startup message and consumes approximately one CPU core:

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makemkvcon -r --cache=1 info dev:/dev/sr0

It made no further visible progress during a 30-second observation and was then terminated. A separate diagnostic run reproduced the stall and was terminated after 20 seconds.

The UHD edition previously produced the same symptom. Multiple MakeMKV background processes accumulated during earlier attempts. The desktop subsequently became unresponsive enough that I rebooted before removing the disc.

Diagnostic log
The diagnostic run ended with these entries. The drive serial number has been removed:

Code: Select all

MakeMKV v2.0.0 linux(x64-release) started
Using 6144KB for read cache.
Network access is ENABLED, CURL version 8.5.0/OpenSSL/3.0.13/1.59.0 (x86_64-pc-linux-gnu), proxy server not set.
DEBUG: Code 0 at ZT1Pm.L!,.E|I0:ZpGU.+S:29393631
No  SDF v0a6: HL-DT-ST_BD-RE_BU40N_1.05_212404231347_[SERIAL REDACTED]
SDF auto v0a6: HL-DT-ST_BD-RE_BU40N_1.05_212404231347_[SERIAL REDACTED]

Other checks
- Linux successfully UDF-mounted the UHD disc during the earlier session.
- No new optical-drive errors appeared in the kernel journal during either controlled ordinary-Blu-ray test.
- The previous boot contained no matching logged kernel lockup, out-of-memory kill, or GPU timeout, and recorded an orderly reboot sequence.
- The older GGC-H20L produces startup “Medium not present” and “unaligned transfer” messages even before MakeMKV runs.
- MakeMKV package verification reported no discrepancies, and its console dependencies resolved.
- No firmware changes have been made during this investigation.

I found a similar BU40N 1.05 Linux report here:
viewtopic.php?t=39043

Is this a known issue with MakeMKV 2.0.0 and this BU40N firmware? What additional diagnostics or reversible software test would you recommend before considering any firmware change?

[Woodstock]

Looks remarkably like this thread: viewtopic.php?t=42751

[jerwal]

Hi Woodstock,

Thanks for the reply and for pointing me towards the other thread.

I've read through it, and the symptoms do appear remarkably similar.

My system is running Linux Mint with MakeMKV 2.0.0, and I have two internal optical drives:

- **LG BU40N** — firmware 1.05, MT1959 platform, LibreDrive status: "Possible, not yet enabled"
- **LG GGC-H20L** — firmware 1.03

The BU40N successfully detects and mounts my *John Wick: Chapter 4* 4K UHD Blu-ray disc under Linux. The kernel recognises it as a BD-ROM with approximately 96 GB capacity.

However, MakeMKV hangs during optical-drive scanning. Multiple `makemkvcon` processes were consuming between 77% and 100% CPU each, and the system eventually became unresponsive, requiring a reboot.

Running `makemkvcon -r --cache=1 info dev:/dev/sr0` directly also stalled after displaying the MakeMKV startup message.

Given the similarities with the other report, I'm wondering whether this could be a regression in MakeMKV 2.0.0's drive enumeration or LibreDrive initialisation.

Has this been reported to the developers, and is there a known fix or workaround?

I also have an external Samsung SE-506BB Blu-ray writer available, so I could test the alternative-drive initialisation workaround mentioned in the other thread if that would help with diagnosis.

I'd appreciate any guidance before considering firmware changes.

Thanks again!