Add a facility to set local/remote video output modeHEADmaster

The current DRM stack requres us to explicitly set the video output
mode between local (BMC) and remote (host). We need to set this mode on
render start/stop, so that the output is set correctly.

This change adds another argument to specify a sysfs file, into which we
set the output mode.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 28 insertions, 5 deletions

diff --git a/uart-render-controller.c b/uart-render-controller.c
index dde6e63..f784933 100644
--- a/uart-render-controller.c
+++ b/uart-render-controller.c
@@ -72,6 +72,7 @@ enum host_state {
 struct render_ctx {
 	enum host_state	state;
 	int		vga_pw_fd;
+	int		video_mode_fd;
 	sd_bus		*bus;
 
 	const char	*service_name;
@@ -94,6 +95,7 @@ static const char *systemd_iface = "org.freedesktop.systemd1.Manager";
 
 static void set_renderer_running(struct render_ctx *ctx, bool running)
 {
+	char buf[] = { '0', '\n' };
 	sd_bus_error e = {0};
 	int rc;
 
@@ -111,12 +113,28 @@ static void set_renderer_running(struct render_ctx *ctx, bool running)
 			ctx->service_name,
 			"replace");
 
-	if (rc < 0)
+	if (rc < 0) {
 		warnx("failed to %s %s: %s\n",
 				running ? "start" : "stop",
 				ctx->service_name,
 				sd_bus_error_is_set(&e) ?
 					e.name : strerror(rc));
+		return;
+	}
+
+	/* 1 for local output, 0 for host */
+	if (running)
+		buf[0] = '1';
+
+	rc = lseek(ctx->video_mode_fd, 0, SEEK_SET);
+	if (rc == -1) {
+		warn("Can't seek video mode reg interface");
+		return;
+	}
+
+	rc = write(ctx->video_mode_fd, buf, sizeof(buf));
+	if (rc < 0)
+		warn("Can't write video mode reg interface");
 }
 
 static int read_vga_pw_reg(struct render_ctx *ctx, uint8_t *regp)
@@ -376,33 +394,38 @@ static int query_initial_state(struct render_ctx *ctx)
 
 static void usage(const char *progname)
 {
-	fprintf(stderr, "usage: %s <VGA-reg> <renderer-service>\n",
+	fprintf(stderr, "usage: %s <VGA-reg> <SCU-reg> <renderer-service>\n",
 			progname);
 }
 
 
 int main(int argc, char **argv)
 {
+	const char *vga_pw_path, *video_mode_path;
 	struct render_ctx _ctx, *ctx;
-	const char *vga_pw_path;
 	char *match;
 	int rc;
 
 	ctx = &_ctx;
 
-	if (argc != 3) {
+	if (argc != 4) {
 		usage(argv[0]);
 		return EXIT_FAILURE;
 	}
 
 	vga_pw_path = argv[1];
-	ctx->service_name = argv[2];
+	video_mode_path = argv[2];
+	ctx->service_name = argv[3];
 
 	ctx->vga_pw_fd = open(vga_pw_path, O_RDONLY);
 	if (ctx->vga_pw_fd < 0)
 		err(EXIT_FAILURE, "can't open VGA scratch regs interface at %s",
 				vga_pw_path);
 
+	ctx->video_mode_fd = open(video_mode_path, O_WRONLY);
+	if (ctx->video_mode_fd < 0)
+		err(EXIT_FAILURE, "can't open video mode reg interface at %s",
+				video_mode_path);
 
 	rc = sd_bus_default(&ctx->bus);
 	if (rc < 0)