[media] exynos4-is: Wait for 100us before opening sensor

Some user space use cases result in kernel hangup on the HIC_OPEN_SENSOR
command write. In case when a minimalistic application is used for setting
up the streaming, the hangups occur only occasionally. In case of GStreamer
use cases it is always the case.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/platform/exynos4-is/fimc-is.c b/drivers/media/platform/exynos4-is/fimc-is.c
index 49658ca..979c388 100644 (file)
--- a/drivers/media/platform/exynos4-is/fimc-is.c
+++ b/drivers/media/platform/exynos4-is/fimc-is.c
@@ -631,6 +631,12 @@ static int fimc_is_hw_open_sensor(struct fimc_is *is,
 
        fimc_is_mem_barrier();
 
+       /*
+        * Some user space use cases hang up here without this
+        * empirically chosen delay.
+        */
+       udelay(100);
+
        mcuctl_write(HIC_OPEN_SENSOR, is, MCUCTL_REG_ISSR(0));
        mcuctl_write(is->sensor_index, is, MCUCTL_REG_ISSR(1));
        mcuctl_write(sensor->drvdata->id, is, MCUCTL_REG_ISSR(2));