blackmagic-10.8.4a4 won't build for kernel 4.9

Hello,

blackmagic-10.8.4a4 and blackmagic-io-10.8.4a4 fail to compile with DKMS on Linux kernel 4.9, which was released in mid-December and is now available in Debian unstable (sid). The compilation failure is due to a relatively simple change (commit 768ae309a96103ed02eb1e111e838c87854d8b51) to the get_user_pages and get_user_pages_remote functions.

Here's some simple patches to resolve the issue. I built the modified code successfully in Linux 4.9.0-1-amd64 #1 SMP Debian 4.9.2-2 (2017-01-12) x86_64 GNU/Linux, and confirmed that my Intensity Pro 4K appears to work properly.

Code: Select all

diff -Naur ./blackmagic_lib.c /usr/src/blackmagic-10.8.4a4/blackmagic_lib.c
--- ./blackmagic_lib.c   2017-01-19 20:33:03.761221314 -0500
+++ /usr/src/blackmagic-10.8.4a4/blackmagic_lib.c   2017-01-19 20:36:35.075101131 -0500
@@ -662,7 +662,12 @@
       write = 0;
    
    down_read(&current_task->mm->mmap_sem);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+      if (current_task == current)
+         ret = get_user_pages((unsigned long)ptr & PAGE_MASK, *nr_pages, write ? FOLL_WRITE : 0 , pages, NULL);
+      else
+         ret = get_user_pages_remote(current_task, current_task->mm, (unsigned long)ptr & PAGE_MASK, *nr_pages, write ? FOLL_WRITE : 0, pages, NULL);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
       if (current_task == current)
          ret = get_user_pages((unsigned long)ptr & PAGE_MASK, *nr_pages, write, 0, pages, NULL);
       else


Code: Select all

diff -Naur ./bm_mm.c /usr/src/blackmagic-io-10.8.4a4/bm_mm.c
--- ./bm_mm.c   2017-01-19 20:33:03.769221561 -0500
+++ /usr/src/blackmagic-io-10.8.4a4/bm_mm.c   2017-01-19 20:37:55.746770949 -0500
@@ -103,7 +103,12 @@
       return false;
 
    down_read(&task->mm->mmap_sem);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+      if (task == current)
+         ret = get_user_pages((unsigned long)address & PAGE_MASK, umem->length, write ? FOLL_WRITE : 0, umem->pages, NULL);
+      else
+         ret = get_user_pages_remote(task, task->mm, (unsigned long)address & PAGE_MASK, umem->length, write ? FOLL_WRITE : 0, umem->pages, NULL);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
       if (task == current)
          ret = get_user_pages((unsigned long)address & PAGE_MASK, umem->length, write, 0, umem->pages, NULL);
       else


(Sorry if this is in the wrong place. I noticed that the earlier incompatibility in this function was also posted here in thread 49626.)

[Nicholas Gill]

Hi Calvin,

Thanks for the detailed report, I have created a ticket so that this can be addressed.

Please note that these are primarily user forums; any enquiries requiring a response from Blackmagic Design are probably best directed to either Blackmagic Design Support for general enquiries, or Blackmagic Design Developer Support (the email address is in the DeckLink SDK manual in section "1.2  Overview") for enquiries relating to any of the Blackmagic Design SDKs and Protocols.

I'm pleased that you have a workaround while the ticket is addressed.

Sincerely,

-nick

Thank you very much for this fix - it worked perfectly!

Thank you Calvin! Terrific fix!