Hi. OBS won’t detect my DeckLink Qaud HDMI Recorder. I have set hardware.decklink.enable = true; and have a package override on obs-studio with decklinkSupport = true;. While OBS shows the “Black Magic Device” input option, no device shows up in the selector. I am using nixpkgs on nixos-25.05. Kernel modules are loaded correctly.
Could this be because of the firmware version mismatch? The drivers should be backwards-compatible as far as I understand BlackMagic’s release notes.
dmesg output:
[ +0.002339] blackmagic: loading out-of-tree module taints kernel.
[ +0.000003] blackmagic: module license 'Proprietary' taints kernel.
[ +0.000001] Disabling lock debugging due to kernel taint
[ +0.000002] blackmagic: module license taints kernel.
[ +0.005119] blackmagic: Loading driver (version: 15.0a62)
[ +0.041262] input: Power Button as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input5
[ +0.000032] ACPI: button: Power Button [PWRB]
[ +0.000042] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input6
[ +0.000154] BlackmagicIO: Driver version 15.0a62 loading
[ +0.000037] blackmagic-io 0000:04:00.0: enabling device (0000 -> 0002)
[ +0.002227] BlackmagicIO: WARNING: "DeckLink Quad HDMI Recorder" has a firmware version mismatch (valid: 1 device: 0x0121 driver: 0x0127)
[ +0.000017] BlackmagicIO: Enabled device "DeckLink Quad HDMI Recorder (1)" x4/5 GT/s (3fb0b10,590400) FW Date: 04-11 23:10
[ +0.002262] BlackmagicIO: DeckLink Quad HDMI Recorder (1) as blackmagic!io0 [0000:04:00.0]
[ +0.000004] BlackmagicIO: Initialised serial driver for blackmagic!io0
[ +0.000916] ACPI: button: Power Button [PWRF]
[ +0.000554] BlackmagicIO: WARNING: "DeckLink Quad HDMI Recorder" has a firmware version mismatch (valid: 1 device: 0x0121 driver: 0x0127)
[ +0.000016] BlackmagicIO: Enabled device "DeckLink Quad HDMI Recorder (2)" x4/5 GT/s (3fb0b11,590401) FW Date: 04-11 23:10
[ +0.002400] BlackmagicIO: DeckLink Quad HDMI Recorder (2) as blackmagic!io1 [0000:04:00.0]
[ +0.000003] BlackmagicIO: Initialised serial driver for blackmagic!io1
[ +0.000228] BlackmagicIO: WARNING: "DeckLink Quad HDMI Recorder" has a firmware version mismatch (valid: 1 device: 0x0121 driver: 0x0127)
[ +0.000014] BlackmagicIO: Enabled device "DeckLink Quad HDMI Recorder (3)" x4/5 GT/s (3fb0b12,590402) FW Date: 04-11 23:10
[ +0.002268] BlackmagicIO: DeckLink Quad HDMI Recorder (3) as blackmagic!io2 [0000:04:00.0]
[ +0.000003] BlackmagicIO: Initialised serial driver for blackmagic!io2
[ +0.004991] BlackmagicIO: WARNING: "DeckLink Quad HDMI Recorder" has a firmware version mismatch (valid: 1 device: 0x0121 driver: 0x0127)
[ +0.000014] BlackmagicIO: Enabled device "DeckLink Quad HDMI Recorder (4)" x4/5 GT/s (3fb0b13,590403) FW Date: 04-11 23:10
[ +0.002448] BlackmagicIO: DeckLink Quad HDMI Recorder (4) as blackmagic!io3 [0000:04:00.0]
[ +0.000003] BlackmagicIO: Initialised serial driver for blackmagic!io3
kmod output:
[root@streaming:~]# kmod list | grep blackmagic
blackmagic_io 2514944 12
blackmagic 827392 0
OBS Blackmagic Device selector:
/proc/ maps for obs:
[root@streaming:~]$ pidof obs
11029
[root@streaming:~]$ cat /proc/11029/maps | grep blackmagic
7f5bbae00000-7f5bbb3df000 r-xp 00000000 00:1c 503154 /nix/store/pr5dsx9pdzrj67nlysis4mj4bbygy8iy-blackmagic-desktop-video-15.0/lib/libDeckLinkAPI.so
7f5bbb3df000-7f5bbb5de000 ---p 005df000 00:1c 503154 /nix/store/pr5dsx9pdzrj67nlysis4mj4bbygy8iy-blackmagic-desktop-video-15.0/lib/libDeckLinkAPI.so
7f5bbb5de000-7f5bbb5ef000 r--p 005de000 00:1c 503154 /nix/store/pr5dsx9pdzrj67nlysis4mj4bbygy8iy-blackmagic-desktop-video-15.0/lib/libDeckLinkAPI.so
7f5bbb5ef000-7f5bbb5f0000 rw-p 005ef000 00:1c 503154 /nix/store/pr5dsx9pdzrj67nlysis4mj4bbygy8iy-blackmagic-desktop-video-15.0/lib/libDeckLinkAPI.so
7f5bbb5fd000-7f5bbb602000 rw-p 006c9000 00:1c 503154 /nix/store/pr5dsx9pdzrj67nlysis4mj4bbygy8iy-blackmagic-desktop-video-15.0/lib/libDeckLinkAPI.so
7f5c4001e000-7f5c4001f000 r--p 1299d1000 00:06 485 /dev/blackmagic/io3
7f5c4001f000-7f5c40020000 r--p 111a75000 00:06 482 /dev/blackmagic/io2
7f5c40020000-7f5c40021000 r--p 111a77000 00:06 481 /dev/blackmagic/io1
7f5c40021000-7f5c40022000 r--p 1271e5000 00:06 480 /dev/blackmagic/io0
7f5c40022000-7f5c40023000 rw-s 00000000 00:16 3 /dev/shm/com_blackmagicdesign_DeckLinkDiscoveryNotifier