intelfb: add vsync interrupt support

[04/05] intelfb: implement FBIO_WAITFORVSYNC ioctl

The (unofficial) FBIO_WAITFORVSYNC ioctl is implemented by sleeping on the appropriate waitqueue, as defined in my earlier patch. Currently, only display 0 (aka pipe A) is supported.

Signed-off-by: Eric Hustvedt <ehustvedt@cecropia.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/video/intelfb/intelfbhw.c b/drivers/video/intelfb/intelfbhw.c
index 1a698a7230e0..0f9631c2ad33 100644
--- a/drivers/video/intelfb/intelfbhw.c
+++ b/drivers/video/intelfb/intelfbhw.c
@@ -2019,3 +2019,36 @@ intelfbhw_disable_irq(struct intelfb_info *dinfo) {
 		free_irq(dinfo->pdev->irq, dinfo);
 	}
 }
+
+int
+intelfbhw_wait_for_vsync(struct intelfb_info *dinfo, u32 pipe) {
+	struct intelfb_vsync *vsync;
+	unsigned int count;
+	int ret;
+
+	switch (pipe) {
+		case 0:
+			vsync = &dinfo->vsync;
+			break;
+		default:
+			return -ENODEV;
+	}
+
+	ret = intelfbhw_enable_irq(dinfo, 0);
+	if (ret) {
+		return ret;
+	}
+
+	count = vsync->count;
+	ret = wait_event_interruptible_timeout(vsync->wait, count != vsync->count, HZ/10);
+	if (ret < 0) {
+		return ret;
+	}
+	if (ret == 0) {
+		intelfbhw_enable_irq(dinfo, 1);
+		DBG_MSG("wait_for_vsync timed out!\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}