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;
+}