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.

Got news: "I am pleased to advise that the recently released Desktop Video 10.8.6 includes the correction for the compilation issue on kernel 4.9+." Testing now

Damn, they should hopefully fix it when Debian/Ubuntu relase the new versions with kernels >= 4.8.

I'm afraid it's even worse, it doesn't compile against 4.9.11-1; note that the driver was not updated, just the desktop app. make -C /lib/modules/`uname -r`/build M=/usr/src/blackmagic-io-10.8.5a4 make[1]: Entering directory '/usr/lib/modules/4.9.11-1-ARCH/build' CC [M] /usr/src/blackmagic-io-10.8.5a4/bm_mm.o /usr/src/blackmagic-io-10.8.5a4/bm_mm.c: In function 'bm_get_user_pages': /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:108:85: error: passing argument 5 of 'get_user_pages' from incompatible pointer type [-Werror=incompatible-pointer-types] ret = get_user_pages((unsigned long)address & PAGE_MASK, umem->length, write, 0, umem->pages, NULL); ^~~~ In file included from /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:27:0: ./include/linux/mm.h:1280:6: note: expected 'struct vm_area_struct **' but argument is of type 'struct page **' long get_user_pages(unsigned long start, unsigned long nr_pages, ^~~~~~~~~~~~~~ /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:108:10: error: too many arguments to function 'get_user_pages' ret = get_user_pages((unsigned long)address & PAGE_MASK, umem->length, write, 0, umem->pages, NULL); ^~~~~~~~~~~~~~ In file included from /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:27:0: ./include/linux/mm.h:1280:6: note: declared here long get_user_pages(unsigned long start, unsigned long nr_pages, ^~~~~~~~~~~~~~ /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:110:108: error: passing argument 7 of 'get_user_pages_remote' from incompatible pointer type [-Werror=incompatible-pointer-types] ret = get_user_pages_remote(task, task->mm, (unsigned long)address & PAGE_MASK, umem->length, write, 0, umem->pages, NULL); ^~~~ In file included from /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:27:0: ./include/linux/mm.h:1276:6: note: expected 'struct vm_area_struct **' but argument is of type 'struct page **' long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, ^~~~~~~~~~~~~~~~~~~~~ /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:110:10: error: too many arguments to function 'get_user_pages_remote' ret = get_user_pages_remote(task, task->mm, (unsigned long)address & PAGE_MASK, umem->length, write, 0, umem->pages, NULL); ^~~~~~~~~~~~~~~~~~~~~ In file included from /usr/src/blackmagic-io-10.8.5a4/bm_mm.c:27:0: ./include/linux/mm.h:1276:6: note: declared here long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, ^~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:294: /usr/src/blackmagic-io-10.8.5a4/bm_mm.o] Error 1 make[1]: *** [Makefile:1490: _module_/usr/src/blackmagic-io-10.8.5a4] Error 2 make[1]: Leaving directory '/usr/lib/modules/4.9.11-1-ARCH/build' make: *** [Makefile:47: all] Error 2

10.8.5 is out, I want to believe.

This is very likely a bug in blackmagic code. The 4.8 kernel introduced CONFIG_HARDENED_USERCOPY, which adds protections to the copying of data to/from userspace. The blackmagic kernel module is out-of-tree and is probably doing something wrong, which the protections are catching. I am not at all interested in fixing their kernel code, though this is possible if somebody has the gumption. You will have to wait until BM releases new modules, or downgrade, or perhaps try recompiling your kernel with CONFIG_HARDENED_USERCOPY unset.

Nope

Yea, that seems like a silly solution downgrade; im using a gtx1080 and im not sure if that solution will support my video card.. ill have to check.. incidentally is this your forum post? https://forum.blackmagicdesign.com/viewtopic.php?f=12&t=53195&p=306662&hilit=Arch+linux#p306662

Yes, 4.4.36-1

Why do i have the sneaky suspicion they (blackmagic) dont really care and are just wanting you (the consumer) to buy their 4k card or something newer.... Using the LTS kernel means reverting from 4.8 to 4.4? edit; guess its happening with the 4k cards as well..

I think that reverting to an LTS kernel is probably your best bet.