As the comment above the defines says, the minimum values are undocumented
so the lowest values seen in register lists are used.

The version of the mt9m114 driver shipped together with the atomisp code
uses 21 for vblank in its register lists, lower MT9M114_MIN_VBLANK
accordingly.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
---
 drivers/media/i2c/mt9m114.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
index d1635f49ee047ca696f6053f6c17e30d736ab795..f63ab4bd040a4a62833d8bc716f94fc29aa03bd7 100644
--- a/drivers/media/i2c/mt9m114.c
+++ b/drivers/media/i2c/mt9m114.c
@@ -329,13 +329,13 @@
 
 /*
  * The minimum amount of horizontal and vertical blanking is undocumented. The
- * minimum values that have been seen in register lists are 303 and 38, use
+ * minimum values that have been seen in register lists are 303 and 21, use
  * them.
  *
  * Set the default to achieve 1280x960 at 30fps with a 48 MHz pixclock.
  */
 #define MT9M114_MIN_HBLANK				303
-#define MT9M114_MIN_VBLANK				38
+#define MT9M114_MIN_VBLANK				21
 #define MT9M114_DEF_HBLANK				323
 #define MT9M114_DEF_VBLANK				39
 

-- 
2.52.0