[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 <[email protected]>
Acked-by: Kyungmin Park <[email protected]>
Cc: Sylwester Nawrocki <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

Author: janaszewski

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));