msm-fb-handle: Adds quirk for msm_mdss_fb.

modules/hardware-qualcomm.nix

@@ -23,6 +23,7 @@ in
     {
       mobile = mkIf cfg.qualcomm-msm8939.enable {
         system.platform = "aarch64-linux";
+        quirks.qualcomm.msm-fb-handle.enable = true;
       };
     }
     {

modules/quirks-qualcomm.nix

@@ -15,16 +15,37 @@ in
         Use sparingly, it is better to patch software to flip buffers instead.
       ";
     };
-  };
-
-  config.mobile.boot = mkIf cfg.msm-fb-refresher.enable {
-    stage-1 = {
-      extraUtils = with pkgs; [
-        msm-fb-refresher
-      ];
-      initFramebuffer = ''
-        msm-fb-refresher --loop &
-      '';
+    quirks.qualcomm.msm-fb-handle.enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = "
+        Enables use of `msm-fb-handle`.
+        This tool keeps a dummy handle open to the framebuffer, useful for msm_mdss
+        which clears and shuts display down when all handles are closed.
+      ";
     };
   };
+
+  config.mobile.boot = mkMerge [
+	(mkIf cfg.msm-fb-handle.enable {
+	  stage-1 = {
+		extraUtils = with pkgs; [
+		  msm-fb-handle
+		];
+		initFramebuffer = ''
+		msm-fb-handle &
+		'';
+	  };
+	})
+	(mkIf cfg.msm-fb-refresher.enable {
+	  stage-1 = {
+		extraUtils = with pkgs; [
+		  msm-fb-refresher
+		];
+		initFramebuffer = ''
+		msm-fb-refresher --loop &
+		'';
+	  };
+	})
+  ];
 }

overlay/msm-fb-handle/default.nix

@@ -0,0 +1,24 @@
+{stdenv}:
+
+let
+  version = "0.1";
+in
+stdenv.mkDerivation {
+  inherit version;
+  name = "msm-fb-handle";
+
+  src = ./main.c;
+  unpackCmd = "mkdir -v src ; cp -v $curSrc src/main.c";
+
+  CC = "${stdenv.cc}/bin/gcc";
+
+  buildPhase = ''
+    $CC main.c -o msm-fb-handle
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp -v msm-fb-handle $out/bin/
+    chmod +x $out/bin/*
+  '';
+}

overlay/msm-fb-handle/main.c

@@ -0,0 +1,18 @@
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+#include <sys/ioctl.h>
+#include <sys/resource.h>
+#include <linux/fb.h>
+
+int main(int argc, char *argv[])
+{
+	int fd = open("/dev/fb0", O_RDWR);
+	setpriority(PRIO_PROCESS, 0, 19);
+	assert(fd >= 0);
+	while(1) {
+		sleep(360000);
+	}
+	close(fd);
+	return 0;
+}

overlay/overlay.nix

@@ -10,6 +10,7 @@ in
     hard-reboot = callPackage ./misc/hard-reboot.nix { };
     mkbootimg = callPackage ./mkbootimg { };
     msm-fb-refresher = callPackage ./msm-fb-refresher { };
+    msm-fb-handle = callPackage ./msm-fb-handle { };
     ply-image = callPackage ./ply-image { };
 
     # Extra "libs"