kernel-configs: Add config fragment for IMSDK

Many GStreamer plugins in the Qualcomm IMSDK use DMABUF userspace heaps,
so provide a kernel config fragment to turn this on and use it in README
and GitHub workflows.

Signed-off-by: Loïc Minier <[email protected]>

Author: lool

.github/workflows/linux.yml

@@ -64,7 +64,9 @@ jobs:
             apt -y install git crossbuild-essential-arm64 make flex bison bc \
                 libdw-dev libelf-dev libssl-dev libssl-dev:arm64 dpkg-dev \
                 debhelper-compat kmod python3 rsync coreutils
-            scripts/build-linux-deb.sh kernel-configs/systemd-boot.config
+            scripts/build-linux-deb.sh \
+                kernel-configs/qcom-imsdk.config \
+                kernel-configs/systemd-boot.config
 
       - name: Stage artifacts for upload
         run: |

README.md

@@ -71,7 +71,7 @@ To build flashable assets for all supported boards, follow these steps:
 
 1. (optional) build a local Linux kernel deb from mainline with a recommended config fragment
     ```bash
-    scripts/build-linux-deb.sh kernel-configs/systemd-boot.config
+    scripts/build-linux-deb.sh kernel-configs/qcom-imsdk.config kernel-configs/systemd-boot.config
     ```
 
 1. build tarballs of the root filesystem and DTBs

kernel-configs/qcom-imsdk.config

@@ -0,0 +1,4 @@
+# many GStreamer plugins in the Qualcomm IMSDK use DMABUF userspace heaps
+CONFIG_DMABUF_HEAPS=y
+CONFIG_DMABUF_HEAPS_SYSTEM=y
+CONFIG_DMABUF_HEAPS_CMA=y