Guennadi Liakhovetski wrote:
On Wed, 20 Jan 2010, Valentin Longchamp wrote:
This prevents the registers to be different to the computed values
the second time you open the same camera with the sames parameters.
The images were different between the first device open and the
second one with the same parameters.
But why they were different? Weren't xskip and yskip preserved from the
previous S_CROP / S_FMT configuration? If so, then, I am afraid, this is
the behaviour, mandated by the API, and as such shall not be changed. Or
have I misunderstood you?
Here are more details about what I debugged:
First more details about what I do with the camera: I open the device,
issue the S_CROP / S_FMT calls and read images, the behaviour is fine,
then close the device.
Then if I reopen the device, reissue the S_CROP / S_FMT calls with the
same params, but the images is not the sames because of different xskip
and yskip. From what I have debugged in the driver at the second S_CROP
/S_FMT, xskip and yskip are computed by mt9t031_skip (and have the same
value that the one stored in the mt9t031 struct) and thus with the
current code are not rewritten.
However, if I read the register values containing bin and skip values on
the camera chip they have been reset (does a open/close do some reset to
the cam ?) and thus different than the ones that should be written.
I hope this clarifies the problem that I am experiencing. I don't think
that the API wants you to get two different images when you open the
device and issue the same parameters twice.
Best Regards
Val
Thanks
Guennadi
Signed-off-by: Valentin Longchamp <valentin.longch...@epfl.ch>
---
drivers/media/video/mt9t031.c | 17 ++++++++---------
1 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/drivers/media/video/mt9t031.c b/drivers/media/video/mt9t031.c
index a9061bf..e4a9095 100644
--- a/drivers/media/video/mt9t031.c
+++ b/drivers/media/video/mt9t031.c
@@ -17,6 +17,7 @@
#include <media/v4l2-chip-ident.h>
#include <media/soc_camera.h>
+
/*
* mt9t031 i2c address 0x5d
* The platform has to define i2c_board_info and link to it from
@@ -337,15 +338,13 @@ static int mt9t031_set_params(struct i2c_client *client,
if (ret >= 0)
ret = reg_write(client, MT9T031_VERTICAL_BLANKING, vblank);
- if (yskip != mt9t031->yskip || xskip != mt9t031->xskip) {
- /* Binning, skipping */
- if (ret >= 0)
- ret = reg_write(client, MT9T031_COLUMN_ADDRESS_MODE,
- ((xbin - 1) << 4) | (xskip - 1));
- if (ret >= 0)
- ret = reg_write(client, MT9T031_ROW_ADDRESS_MODE,
- ((ybin - 1) << 4) | (yskip - 1));
- }
+ /* Binning, skipping */
+ if (ret >= 0)
+ ret = reg_write(client, MT9T031_COLUMN_ADDRESS_MODE,
+ ((xbin - 1) << 4) | (xskip - 1));
+ if (ret >= 0)
+ ret = reg_write(client, MT9T031_ROW_ADDRESS_MODE,
+ ((ybin - 1) << 4) | (yskip - 1));
dev_dbg(&client->dev, "new physical left %u, top %u\n",
rect->left, rect->top);
--
1.6.3.3
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
--
Valentin Longchamp, PhD Student, EPFL-STI-LSRO1
valentin.longch...@epfl.ch, Phone: +41216937827
http://people.epfl.ch/valentin.longchamp
MEB3494, Station 9, CH-1015 Lausanne
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