Arch Linux User Repository

I finally had time to investigate the issue. It looks like that as of 11.5, the DesktopVideoHelper.service has to be running for the capture card to work properly.

@archismo

Did you have to do anything other than starting the service to get it working on Cachy? Tried:

linux-cachyos 6.18.5-2 linux-cachyos 6.18.5-2

also tried disabling amd_ioummu and disabling aspm

I can't get it to work, sometimes after a cold boot it will be recognized by the Desktop Video GUI app, other times it won't. But it's never recognized by Resolve.

Resolve itself says no cards are detected:

0x7fa4f2643000 | SyManager.DeckLink   | INFO  | 2026-01-18 20:27:26,425 | DL::DisplayDevices: (0/0)
0x7fa4f2643000 | Main                 | INFO  | 2026-01-18 20:27:26,425 | Decklink model name: '', version: '15.3.1'
0x7fa4f2643000 | DVIP                 | INFO  | 2026-01-18 20:27:26,425 | DVIP release/20.3.1 build 2 (75d1a0a8f320380f0522c8b0de3b78480f5d08e8). Release, version 20.3.1.

dmesg shows the driver initializing

[34979.505674] BlackmagicIO: Enabled device "DeckLink Mini Monitor 4K" x4/5 GT/s (240a1639,531000) FW Date: 03-19 10:23
[34979.508195] BlackmagicIO: DeckLink Mini Monitor 4K as blackmagic!io0 [0000:10:00.0]
[34979.508198] BlackmagicIO: Initialised serial driver for blackmagic!io0

If the card is detected by the GUI decklink software, it will not be detected after starting resolve.

Sometimes after booting, I will get a pile of popups saying that a firmware update is required. This is not true, confirmed in win11 on the same system. If I click update on one of these, it causes an instant black-screen. No record of crash in the kernel logs.

I tested this in arch and cachyos. It installs fine, and gui windows show up. But the card is not recognised. command 'DesktopVideoUpdateTool -l' shows: Available Devices: * DeckLink Mini Monitor HD (P8674f220) Firmware is up to date

Edit: i got it working. I had to enable DesktopVideoHelper.service and start it. It looks like DesktopVideoHelper is installed with disabled status. Can this be fixed in package? Same issue is with opensuse too.

@archismo You should use the "Flag package out-of-date" link for this. I just did for the 15.0 release.

decklink v 15.0 is released. When will this package be updated?

Here's the patch with corrected paths that works for me. Just drop this into a file called linux-6.15.patch in the same directory as PKGBUILD, edit the sha256sums to contain the new output of makepkg -g:

sha256sums=('5230976612ff069f90920ba60e21f569c07dbb2fb0d9db3f9d72c871f1cf8bb6'
            '74966c45f91fcd715c1170df969f75bd2f669b2b65f32db679bbbece8cbd20b7'
            '1700f833f17608dc474c387f21c65ec4ca3537b9f892619063976ca185b9308e')

And then it builds and works. Here's the patch:

--- a/blackmagic-io-14.4.1a4/bm_util.c  2025-01-24 02:38:07.000000000 -0800
+++ b/blackmagic-io-14.4.1a4/bm_util.c  2025-06-28 12:02:11.250808368 -0700
@@ -471,7 +471,7 @@
 {
 #if KERNEL_VERSION_OR_LATER(4, 15, 0)
    struct bm_timer_wrapper* timer_wrapper = container_of(timer, struct bm_timer_wrapper, timer);
-   del_timer(timer);
+   timer_delete(timer);
    bm_kfree(timer_wrapper);
 #else
    del_timer(timer);
@@ -491,7 +491,7 @@

 void bm_timer_cancel(bm_timer_t* timer)
 {
-   del_timer_sync(timer);
+   timer_delete_sync(timer);
 }

 // Event waiting

Confirmed that patch from @sudomateo works with 6.15.2

I received the following error on kernel 6.15.1-arch1-2.

bm_util.c: In function ‘bm_timer_free’:
bm_util.c:474:9: error: implicit declaration of function ‘del_timer’; did you mean ‘add_timer’? [-Wimplicit-function-declaration]
  474 |         del_timer(timer);
      |         ^~~~~~~~~
      |         add_timer
bm_util.c: In function ‘bm_timer_cancel’:
bm_util.c:494:9: error: implicit declaration of function ‘del_timer_sync’ [-Wimplicit-function-declaration]
  494 |         del_timer_sync(timer);
      |         ^~~~~~~~~~~~~~

I updated the source with the following patch and was successfully able to build kernel module again.

diff --git a/var/lib/dkms/blackmagic-io/14.4.1a4/source/bm_util.c b/var/lib/dkms/blackmagic-io/14.4.1a4/source/bm_util.c
index 66751cb..2f05d0e 100644
--- a/var/lib/dkms/blackmagic-io/14.4.1a4/source/bm_util.c
+++ b/var/lib/dkms/blackmagic-io/14.4.1a4/source/bm_util.c
@@ -471,7 +471,7 @@ void bm_timer_free(bm_timer_t* timer)
 {
 #if KERNEL_VERSION_OR_LATER(4, 15, 0)
        struct bm_timer_wrapper* timer_wrapper = container_of(timer, struct bm_timer_wrapper, timer);
-       del_timer(timer);
+       timer_delete(timer);
        bm_kfree(timer_wrapper);
 #else
        del_timer(timer);
@@ -491,7 +491,7 @@ void bm_timer_expire_at(bm_timer_t* timer, uint64_t ns)

 void bm_timer_cancel(bm_timer_t* timer)
 {
-       del_timer_sync(timer);
+       timer_delete_sync(timer);
 }

 // Event waiting

Would you consider adding -Wno-error=strict-prototypes flag to the Makefile? This is needed to prevent build failures when compiling against Clang/LLVM-based kernels, as Clang treats function declarations without prototypes as an error by default.

This change would suppress those specific warnings being treated as fatal, without impacting builds on GCC or weakening general warning coverage.

Temporary workaround: edit /usr/src/blackmagic-io-14.4.1a4/dkms.conf and /usr/src/blackmagic-14.4.1a4/dkms.conf and change MAKE="make KERNELRELEASE=$kernelver" to MAKE="make KERNELRELEASE=$kernelver EXTRA_CFLAGS="-Wno-error=strict-prototypes""

also a friendly reminder to check for firmware updates when troubleshooting the driver. in this case a firmware update was required (for a Decklink Duo 2), which made it not appear in BlackmagicDesktopVideoSetup or other softwares, even if the driver was functionning.

once the driver is working (and service running), DesktopVideoUpdateTool -l will list outdated cards that are otherwise unreported by BlackmagicDesktopVideoSetup.

the fix works on 6.13.2-arch1-1 but it did not compile for 6.12.13-1-lts with

libbpf: failed to get e_shstrndx from vmlinux Fail
ed to parse base BTF 'vmlinux': -4001 

i don't think this is a Decklink issue; this machine was a bit long in the updates (perhaps 9 months) but just in case someone else faces the same thing: had to run sudo pacman -S linux-lts-headers (even if it was already installed and fresh out of an -Syu prior to trying to update Decklink) which triggered DKMS and compiled correctly for LTS. don't know enough about PKGBUILD to suggest if something should be included to prevent such issues.