mt9m111/mt9m131: kernel 3.8 issues.

mt9m111/mt9m131: kernel 3.8 issues.

[javier Martin]

Hi,
I am testing mt9m131 sensor (which is supported in mt9m111.c) in
mainline kernel 3.8 with my Visstrim M10, which is an i.MX27 board.

Since both mx2_camera.c and mt9m111.c are soc_camera drivers making it
work was quite straightforward. However, I've found several issues
regarding mt9m111.c:

1. mt9m111 probe is broken. It will give an oops since it tries to use
a context before it's been assigned.
2. mt9m111 auto exposure control is broken too (see the patch below).
3. After I've fixed 1 and 2 the colours in the pictures I grab are
dull and not vibrant, green is very dark and red seems like pink, blue
and yellow look fine though. I have both auto exposure and auto white
balance enabled.

I can see in the list that you have tried this sensor before. Have you
also noticed these problems (specially 3)?

This patch is just to provide a quick fix for points 1 and 2 just in
case you feel like testing this in kernel 3.8. If you consider these
fix are valid I'll send a proper patch later:

diff --git a/drivers/media/i2c/soc_camera/mt9m111.c
b/drivers/media/i2c/soc_camera/mt9m111.c
index 62fd94a..7d99655 100644
--- a/drivers/media/i2c/soc_camera/mt9m111.c
+++ b/drivers/media/i2c/soc_camera/mt9m111.c
@@ -704,7 +704,7 @@ static int mt9m111_set_autoexposure(struct mt9m111
*mt9m111, int on)
 {
        struct i2c_client *client = v4l2_get_subdevdata(&mt9m111->subdev);

-       if (on)
+       if (on == V4L2_EXPOSURE_AUTO)
                return reg_set(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
        return reg_clear(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
 }
@@ -916,6 +916,9 @@ static int mt9m111_video_probe(struct i2c_client *client)
        s32 data;
        int ret;

+       /* Assign context to avoid oops */
+       mt9m111->ctx = &context_a;
+
        ret = mt9m111_s_power(&mt9m111->subdev, 1);
        if (ret < 0)
                return ret;


Regards.

-- 
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
www.vista-silicon.com

Re: mt9m111/mt9m131: kernel 3.8 issues.

[Benoît Thébaudeau]

Dear Javier Martin,

On Thursday, March 7, 2013 10:43:42 AM, Javier Martin wrote:
> Hi,
> I am testing mt9m131 sensor (which is supported in mt9m111.c) in
> mainline kernel 3.8 with my Visstrim M10, which is an i.MX27 board.
> 
> Since both mx2_camera.c and mt9m111.c are soc_camera drivers making it
> work was quite straightforward. However, I've found several issues
> regarding mt9m111.c:
> 
> 1. mt9m111 probe is broken. It will give an oops since it tries to use
> a context before it's been assigned.
> 2. mt9m111 auto exposure control is broken too (see the patch below).
> 3. After I've fixed 1 and 2 the colours in the pictures I grab are
> dull and not vibrant, green is very dark and red seems like pink, blue
> and yellow look fine though. I have both auto exposure and auto white
> balance enabled.
> 
> I can see in the list that you have tried this sensor before. Have you
> also noticed these problems (specially 3)?

I am using the MT9M131 with an i.MX35 board and Linux 3.4.5. It works nicely. I
have not noticed 1 and 3. However, I have noticed 2, for which I already have
posted a patch (here: https://patchwork.kernel.org/patch/2187291/), but I have
not yet received any feedback.

> This patch is just to provide a quick fix for points 1 and 2 just in
> case you feel like testing this in kernel 3.8. If you consider these
> fix are valid I'll send a proper patch later:

It's not straightforward to port my board to 3.8, but I've just reviewed the
code in linux-next (see below).

> diff --git a/drivers/media/i2c/soc_camera/mt9m111.c
> b/drivers/media/i2c/soc_camera/mt9m111.c
> index 62fd94a..7d99655 100644
> --- a/drivers/media/i2c/soc_camera/mt9m111.c
> +++ b/drivers/media/i2c/soc_camera/mt9m111.c
> @@ -704,7 +704,7 @@ static int mt9m111_set_autoexposure(struct mt9m111
> *mt9m111, int on)
>  {
>         struct i2c_client *client = v4l2_get_subdevdata(&mt9m111->subdev);
> 
> -       if (on)
> +       if (on == V4L2_EXPOSURE_AUTO)
>                 return reg_set(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
>         return reg_clear(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
>  }

This hunk does the same thing as my patch mentioned above, so please don't send
anything for that.

> @@ -916,6 +916,9 @@ static int mt9m111_video_probe(struct i2c_client *client)
>         s32 data;
>         int ret;
> 
> +       /* Assign context to avoid oops */
> +       mt9m111->ctx = &context_a;
> +
>         ret = mt9m111_s_power(&mt9m111->subdev, 1);
>         if (ret < 0)
>                 return ret;

There is indeed a bug, introduced by commit 4bbc6d5. The issue is:
 mt9m111_set_context(mt9m111, mt9m111->ctx);
in mt9m111_restore_state() called (indirectly) from mt9m111_s_power() from
mt9m111_video_probe() with ctx still NULL, before mt9m111_init() has been called
to initialize ctx to &context_b.

So the fix would not be what you did, but rather to reorganize things a little
bit to avoid this out-of-order init and use of ctx.

Best regards,
Benoît

Re: mt9m111/mt9m131: kernel 3.8 issues.

[javier Martin]

Hi Benoît,
thank you for your answer.

On 7 March 2013 13:13, Benoît Thébaudeau <benoit.thebaudeau@advansee.com> wrote:
> Dear Javier Martin,
>
> On Thursday, March 7, 2013 10:43:42 AM, Javier Martin wrote:
>> Hi,
>> I am testing mt9m131 sensor (which is supported in mt9m111.c) in
>> mainline kernel 3.8 with my Visstrim M10, which is an i.MX27 board.
>>
>> Since both mx2_camera.c and mt9m111.c are soc_camera drivers making it
>> work was quite straightforward. However, I've found several issues
>> regarding mt9m111.c:
>>
>> 1. mt9m111 probe is broken. It will give an oops since it tries to use
>> a context before it's been assigned.
>> 2. mt9m111 auto exposure control is broken too (see the patch below).
>> 3. After I've fixed 1 and 2 the colours in the pictures I grab are
>> dull and not vibrant, green is very dark and red seems like pink, blue
>> and yellow look fine though. I have both auto exposure and auto white
>> balance enabled.
>>
>> I can see in the list that you have tried this sensor before. Have you
>> also noticed these problems (specially 3)?
>
> I am using the MT9M131 with an i.MX35 board and Linux 3.4.5. It works nicely. I
> have not noticed 1 and 3. However, I have noticed 2, for which I already have
> posted a patch (here: https://patchwork.kernel.org/patch/2187291/), but I have
> not yet received any feedback.

I've just added my Tested-By to your patch, and it seems Guennadi will
merge it. So, we don't have to worry about 2 any more.

Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
migrated my code to that version but I still get colours that lack
enough intensity.
This is a snapshot "a" taken with my mobile which is much more similar
to what I can really see with my eyes:
http://img96.imageshack.us/img96/1451/20130307171334.jpg

This is a similar snapshot "b" taken with mt9m131 in my board. It
shows that colours tend to be dull and darker, specially green:
http://img703.imageshack.us/img703/6025/testgo.jpg

Are the snapshots you take with your HW  more similar to "a" or to
"b"? Perhaps I am being too picky with the image quality and this is
all what mt9m131 can do?

>> This patch is just to provide a quick fix for points 1 and 2 just in
>> case you feel like testing this in kernel 3.8. If you consider these
>> fix are valid I'll send a proper patch later:
>
> It's not straightforward to port my board to 3.8, but I've just reviewed the
> code in linux-next (see below).
>
>> diff --git a/drivers/media/i2c/soc_camera/mt9m111.c
>> b/drivers/media/i2c/soc_camera/mt9m111.c
>> index 62fd94a..7d99655 100644
>> --- a/drivers/media/i2c/soc_camera/mt9m111.c
>> +++ b/drivers/media/i2c/soc_camera/mt9m111.c
>> @@ -704,7 +704,7 @@ static int mt9m111_set_autoexposure(struct mt9m111
>> *mt9m111, int on)
>>  {
>>         struct i2c_client *client = v4l2_get_subdevdata(&mt9m111->subdev);
>>
>> -       if (on)
>> +       if (on == V4L2_EXPOSURE_AUTO)
>>                 return reg_set(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
>>         return reg_clear(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
>>  }
>
> This hunk does the same thing as my patch mentioned above, so please don't send
> anything for that.

Sure.

>> @@ -916,6 +916,9 @@ static int mt9m111_video_probe(struct i2c_client *client)
>>         s32 data;
>>         int ret;
>>
>> +       /* Assign context to avoid oops */
>> +       mt9m111->ctx = &context_a;
>> +
>>         ret = mt9m111_s_power(&mt9m111->subdev, 1);
>>         if (ret < 0)
>>                 return ret;
>
> There is indeed a bug, introduced by commit 4bbc6d5. The issue is:
>  mt9m111_set_context(mt9m111, mt9m111->ctx);
> in mt9m111_restore_state() called (indirectly) from mt9m111_s_power() from
> mt9m111_video_probe() with ctx still NULL, before mt9m111_init() has been called
> to initialize ctx to &context_b.
>
> So the fix would not be what you did, but rather to reorganize things a little
> bit to avoid this out-of-order init and use of ctx.

Thanks, I will take a look at the offending commit and try to
reorganize the code properly.

Regards.
-- 
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
www.vista-silicon.com

Re: mt9m111/mt9m131: kernel 3.8 issues.

[Benoît Thébaudeau]

Hi Javier,

On Friday, March 8, 2013 8:55:25 AM, Javier Martin wrote:
> Hi Benoît,
> thank you for your answer.

You're welcome.

> On 7 March 2013 13:13, Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
> wrote:
> > Dear Javier Martin,
> >
> > On Thursday, March 7, 2013 10:43:42 AM, Javier Martin wrote:
> >> Hi,
> >> I am testing mt9m131 sensor (which is supported in mt9m111.c) in
> >> mainline kernel 3.8 with my Visstrim M10, which is an i.MX27 board.
> >>
> >> Since both mx2_camera.c and mt9m111.c are soc_camera drivers making it
> >> work was quite straightforward. However, I've found several issues
> >> regarding mt9m111.c:
> >>
> >> 1. mt9m111 probe is broken. It will give an oops since it tries to use
> >> a context before it's been assigned.
> >> 2. mt9m111 auto exposure control is broken too (see the patch below).
> >> 3. After I've fixed 1 and 2 the colours in the pictures I grab are
> >> dull and not vibrant, green is very dark and red seems like pink, blue
> >> and yellow look fine though. I have both auto exposure and auto white
> >> balance enabled.
> >>
> >> I can see in the list that you have tried this sensor before. Have you
> >> also noticed these problems (specially 3)?
> >
> > I am using the MT9M131 with an i.MX35 board and Linux 3.4.5. It works
> > nicely. I
> > have not noticed 1 and 3. However, I have noticed 2, for which I already
> > have
> > posted a patch (here: https://patchwork.kernel.org/patch/2187291/), but I
> > have
> > not yet received any feedback.
> 
> I've just added my Tested-By to your patch, and it seems Guennadi will
> merge it. So, we don't have to worry about 2 any more.

Thanks for that.

> Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
> migrated my code to that version but I still get colours that lack
> enough intensity.
> This is a snapshot "a" taken with my mobile which is much more similar
> to what I can really see with my eyes:
> http://img96.imageshack.us/img96/1451/20130307171334.jpg
> 
> This is a similar snapshot "b" taken with mt9m131 in my board. It
> shows that colours tend to be dull and darker, specially green:
> http://img703.imageshack.us/img703/6025/testgo.jpg
> 
> Are the snapshots you take with your HW  more similar to "a" or to
> "b"? Perhaps I am being too picky with the image quality and this is
> all what mt9m131 can do?

I fear that my captures are closer to "b". Your description of "3" was giving
the impression of flashy colors. But the impression that this sensor gives me is
rather a superimposed gray film. This effect is more or less visible depending
on the lighting conditions, but it never seems to produce high quality colors.

> >> This patch is just to provide a quick fix for points 1 and 2 just in
> >> case you feel like testing this in kernel 3.8. If you consider these
> >> fix are valid I'll send a proper patch later:
> >
> > It's not straightforward to port my board to 3.8, but I've just reviewed
> > the
> > code in linux-next (see below).
> >
> >> diff --git a/drivers/media/i2c/soc_camera/mt9m111.c
> >> b/drivers/media/i2c/soc_camera/mt9m111.c
> >> index 62fd94a..7d99655 100644
> >> --- a/drivers/media/i2c/soc_camera/mt9m111.c
> >> +++ b/drivers/media/i2c/soc_camera/mt9m111.c
> >> @@ -704,7 +704,7 @@ static int mt9m111_set_autoexposure(struct mt9m111
> >> *mt9m111, int on)
> >>  {
> >>         struct i2c_client *client = v4l2_get_subdevdata(&mt9m111->subdev);
> >>
> >> -       if (on)
> >> +       if (on == V4L2_EXPOSURE_AUTO)
> >>                 return reg_set(OPER_MODE_CTRL,
> >>                 MT9M111_OPMODE_AUTOEXPO_EN);
> >>         return reg_clear(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
> >>  }
> >
> > This hunk does the same thing as my patch mentioned above, so please don't
> > send
> > anything for that.
> 
> Sure.
> 
> >> @@ -916,6 +916,9 @@ static int mt9m111_video_probe(struct i2c_client
> >> *client)
> >>         s32 data;
> >>         int ret;
> >>
> >> +       /* Assign context to avoid oops */
> >> +       mt9m111->ctx = &context_a;
> >> +
> >>         ret = mt9m111_s_power(&mt9m111->subdev, 1);
> >>         if (ret < 0)
> >>                 return ret;
> >
> > There is indeed a bug, introduced by commit 4bbc6d5. The issue is:
> >  mt9m111_set_context(mt9m111, mt9m111->ctx);
> > in mt9m111_restore_state() called (indirectly) from mt9m111_s_power() from
> > mt9m111_video_probe() with ctx still NULL, before mt9m111_init() has been
> > called
> > to initialize ctx to &context_b.
> >
> > So the fix would not be what you did, but rather to reorganize things a
> > little
> > bit to avoid this out-of-order init and use of ctx.
> 
> Thanks, I will take a look at the offending commit and try to
> reorganize the code properly.

Thanks for working on it. I will probably need this fix too later.

Best regards,
Benoît

Re: mt9m111/mt9m131: kernel 3.8 issues.

[javier Martin]

Hi Benoît,

On 8 March 2013 12:53, Benoît Thébaudeau <benoit.thebaudeau@advansee.com> wrote:
>
>> Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
>> migrated my code to that version but I still get colours that lack
>> enough intensity.
>> This is a snapshot "a" taken with my mobile which is much more similar
>> to what I can really see with my eyes:
>> http://img96.imageshack.us/img96/1451/20130307171334.jpg
>>
>> This is a similar snapshot "b" taken with mt9m131 in my board. It
>> shows that colours tend to be dull and darker, specially green:
>> http://img703.imageshack.us/img703/6025/testgo.jpg
>>
>> Are the snapshots you take with your HW  more similar to "a" or to
>> "b"? Perhaps I am being too picky with the image quality and this is
>> all what mt9m131 can do?
>
> I fear that my captures are closer to "b". Your description of "3" was giving
> the impression of flashy colors. But the impression that this sensor gives me is
> rather a superimposed gray film. This effect is more or less visible depending
> on the lighting conditions, but it never seems to produce high quality colors.

Yes, yours is probably is the best description for the image quality
this sensor provides with the current settings.
Well, this is a bit disappointing. Let's see if some other user has a
similar experience with it or comes up with a way to improve it.

I've tested several things such as disabling auto white balance and
auto exposure and try to manually change colour gains but it seems the
sensor simply ignores the latter.

There is an evaluation board  from Aptina
(http://www.digikey.com/product-detail/es/MT9M131C12STCH%20ES/557-1251-ND/1643271)
but, unfortunately, I don't have one of these available. It could be
very useful to test the sensor with this board with the configuration
Aptina recommends and see whether the "grey layer effect" still
persists.

I will try to contact Aptina's technical support but, according to my
previous experience, there is no guarantee we get a clarifying answer.
I'll keep you updated nevertheless.

Regards.
-- 
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
www.vista-silicon.com

Re: mt9m111/mt9m131: kernel 3.8 issues.

[Benoît Thébaudeau]

Hi Javier,

On Friday, March 8, 2013 1:37:38 PM, Javier Martin wrote:
> Hi Benoît,
> 
> On 8 March 2013 12:53, Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
> wrote:
> >
> >> Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
> >> migrated my code to that version but I still get colours that lack
> >> enough intensity.
> >> This is a snapshot "a" taken with my mobile which is much more similar
> >> to what I can really see with my eyes:
> >> http://img96.imageshack.us/img96/1451/20130307171334.jpg
> >>
> >> This is a similar snapshot "b" taken with mt9m131 in my board. It
> >> shows that colours tend to be dull and darker, specially green:
> >> http://img703.imageshack.us/img703/6025/testgo.jpg
> >>
> >> Are the snapshots you take with your HW  more similar to "a" or to
> >> "b"? Perhaps I am being too picky with the image quality and this is
> >> all what mt9m131 can do?
> >
> > I fear that my captures are closer to "b". Your description of "3" was
> > giving
> > the impression of flashy colors. But the impression that this sensor gives
> > me is
> > rather a superimposed gray film. This effect is more or less visible
> > depending
> > on the lighting conditions, but it never seems to produce high quality
> > colors.
> 
> Yes, yours is probably is the best description for the image quality
> this sensor provides with the current settings.
> Well, this is a bit disappointing. Let's see if some other user has a
> similar experience with it or comes up with a way to improve it.
> 
> I've tested several things such as disabling auto white balance and
> auto exposure and try to manually change colour gains but it seems the
> sensor simply ignores the latter.
> 
> There is an evaluation board  from Aptina
> (http://www.digikey.com/product-detail/es/MT9M131C12STCH%20ES/557-1251-ND/1643271)
> but, unfortunately, I don't have one of these available. It could be
> very useful to test the sensor with this board with the configuration
> Aptina recommends and see whether the "grey layer effect" still
> persists.

It is perhaps also possible to find their recommended register settings
somewhere without having this evaluation board.

> I will try to contact Aptina's technical support but, according to my
> previous experience, there is no guarantee we get a clarifying answer.
> I'll keep you updated nevertheless.

Thanks.

Best regards,
Benoît

Re: mt9m111/mt9m131: kernel 3.8 issues.

[Guennadi Liakhovetski]

On Thu, 7 Mar 2013, javier Martin wrote:

> Hi,
> I am testing mt9m131 sensor (which is supported in mt9m111.c) in
> mainline kernel 3.8 with my Visstrim M10, which is an i.MX27 board.
> 
> Since both mx2_camera.c and mt9m111.c are soc_camera drivers making it
> work was quite straightforward. However, I've found several issues
> regarding mt9m111.c:
> 
> 1. mt9m111 probe is broken. It will give an oops since it tries to use
> a context before it's been assigned.
> 2. mt9m111 auto exposure control is broken too (see the patch below).
> 3. After I've fixed 1 and 2 the colours in the pictures I grab are
> dull and not vibrant, green is very dark and red seems like pink, blue
> and yellow look fine though. I have both auto exposure and auto white
> balance enabled.
> 
> I can see in the list that you have tried this sensor before. Have you
> also noticed these problems (specially 3)?
> 
> This patch is just to provide a quick fix for points 1 and 2 just in
> case you feel like testing this in kernel 3.8. If you consider these
> fix are valid I'll send a proper patch later:
> 
> diff --git a/drivers/media/i2c/soc_camera/mt9m111.c
> b/drivers/media/i2c/soc_camera/mt9m111.c
> index 62fd94a..7d99655 100644
> --- a/drivers/media/i2c/soc_camera/mt9m111.c
> +++ b/drivers/media/i2c/soc_camera/mt9m111.c
> @@ -704,7 +704,7 @@ static int mt9m111_set_autoexposure(struct mt9m111
> *mt9m111, int on)
>  {
>         struct i2c_client *client = v4l2_get_subdevdata(&mt9m111->subdev);
> 
> -       if (on)
> +       if (on == V4L2_EXPOSURE_AUTO)
>                 return reg_set(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
>         return reg_clear(OPER_MODE_CTRL, MT9M111_OPMODE_AUTOEXPO_EN);
>  }
> @@ -916,6 +916,9 @@ static int mt9m111_video_probe(struct i2c_client *client)
>         s32 data;
>         int ret;
> 
> +       /* Assign context to avoid oops */
> +       mt9m111->ctx = &context_a;
> +
>         ret = mt9m111_s_power(&mt9m111->subdev, 1);
>         if (ret < 0)
>                 return ret;

Yes, there is an Oops currently in mt9m111, that this patch would fix, 
thanks! But please, do it a bit differently: please, move the lines

	/* Default HIGHPOWER context */
	mt9m111->ctx = &context_b;

from mt9m111_init() to probing, instead of adding a context_a selection. 
And I think it would be more logical to move those lines to 
mt9m111_probe(), directly below the mt9m111 allocation, not to 
mt9m111_video_probe(). Please, make this change and submit a patch.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: mt9m111/mt9m131: kernel 3.8 issues.

[Guennadi Liakhovetski]

On Fri, 8 Mar 2013, Benoît Thébaudeau wrote:

> Hi Javier,
> 
> On Friday, March 8, 2013 1:37:38 PM, Javier Martin wrote:
> > Hi Benoît,
> > 
> > On 8 March 2013 12:53, Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
> > wrote:
> > >
> > >> Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
> > >> migrated my code to that version but I still get colours that lack
> > >> enough intensity.
> > >> This is a snapshot "a" taken with my mobile which is much more similar
> > >> to what I can really see with my eyes:
> > >> http://img96.imageshack.us/img96/1451/20130307171334.jpg
> > >>
> > >> This is a similar snapshot "b" taken with mt9m131 in my board. It
> > >> shows that colours tend to be dull and darker, specially green:
> > >> http://img703.imageshack.us/img703/6025/testgo.jpg
> > >>
> > >> Are the snapshots you take with your HW  more similar to "a" or to
> > >> "b"? Perhaps I am being too picky with the image quality and this is
> > >> all what mt9m131 can do?
> > >
> > > I fear that my captures are closer to "b". Your description of "3" was
> > > giving
> > > the impression of flashy colors. But the impression that this sensor gives
> > > me is
> > > rather a superimposed gray film. This effect is more or less visible
> > > depending
> > > on the lighting conditions, but it never seems to produce high quality
> > > colors.
> > 
> > Yes, yours is probably is the best description for the image quality
> > this sensor provides with the current settings.
> > Well, this is a bit disappointing. Let's see if some other user has a
> > similar experience with it or comes up with a way to improve it.
> > 
> > I've tested several things such as disabling auto white balance and
> > auto exposure and try to manually change colour gains but it seems the
> > sensor simply ignores the latter.
> > 
> > There is an evaluation board  from Aptina
> > (http://www.digikey.com/product-detail/es/MT9M131C12STCH%20ES/557-1251-ND/1643271)
> > but, unfortunately, I don't have one of these available. It could be
> > very useful to test the sensor with this board with the configuration
> > Aptina recommends and see whether the "grey layer effect" still
> > persists.
> 
> It is perhaps also possible to find their recommended register settings
> somewhere without having this evaluation board.

I just tested my mt9m131 camera on a i.MX31 board, if not this your email 
I don't think I'd be alarmed by the image quality it's producing, maybe 
I'm just less picky:-) And yes, in general I agree, I think, this level of 
image quality tuning is difficult to achieve on modern cameras with 100s 
of fine-tuning knobs. I'll try to re-test this camera in day light 
conditions and post my best shot :)

Thanks
Guennadi

> > I will try to contact Aptina's technical support but, according to my
> > previous experience, there is no guarantee we get a clarifying answer.
> > I'll keep you updated nevertheless.
> 
> Thanks.
> 
> Best regards,
> Benoît
> 

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: mt9m111/mt9m131: kernel 3.8 issues.

[Guennadi Liakhovetski]

On Fri, 8 Mar 2013, Guennadi Liakhovetski wrote:

> On Fri, 8 Mar 2013, Benoît Thébaudeau wrote:
> 
> > Hi Javier,
> > 
> > On Friday, March 8, 2013 1:37:38 PM, Javier Martin wrote:
> > > Hi Benoît,
> > > 
> > > On 8 March 2013 12:53, Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
> > > wrote:
> > > >
> > > >> Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
> > > >> migrated my code to that version but I still get colours that lack
> > > >> enough intensity.
> > > >> This is a snapshot "a" taken with my mobile which is much more similar
> > > >> to what I can really see with my eyes:
> > > >> http://img96.imageshack.us/img96/1451/20130307171334.jpg
> > > >>
> > > >> This is a similar snapshot "b" taken with mt9m131 in my board. It
> > > >> shows that colours tend to be dull and darker, specially green:
> > > >> http://img703.imageshack.us/img703/6025/testgo.jpg
> > > >>
> > > >> Are the snapshots you take with your HW  more similar to "a" or to
> > > >> "b"? Perhaps I am being too picky with the image quality and this is
> > > >> all what mt9m131 can do?
> > > >
> > > > I fear that my captures are closer to "b". Your description of "3" was
> > > > giving
> > > > the impression of flashy colors. But the impression that this sensor gives
> > > > me is
> > > > rather a superimposed gray film. This effect is more or less visible
> > > > depending
> > > > on the lighting conditions, but it never seems to produce high quality
> > > > colors.
> > > 
> > > Yes, yours is probably is the best description for the image quality
> > > this sensor provides with the current settings.
> > > Well, this is a bit disappointing. Let's see if some other user has a
> > > similar experience with it or comes up with a way to improve it.
> > > 
> > > I've tested several things such as disabling auto white balance and
> > > auto exposure and try to manually change colour gains but it seems the
> > > sensor simply ignores the latter.
> > > 
> > > There is an evaluation board  from Aptina
> > > (http://www.digikey.com/product-detail/es/MT9M131C12STCH%20ES/557-1251-ND/1643271)
> > > but, unfortunately, I don't have one of these available. It could be
> > > very useful to test the sensor with this board with the configuration
> > > Aptina recommends and see whether the "grey layer effect" still
> > > persists.
> > 
> > It is perhaps also possible to find their recommended register settings
> > somewhere without having this evaluation board.
> 
> I just tested my mt9m131 camera on a i.MX31 board, if not this your email 
> I don't think I'd be alarmed by the image quality it's producing, maybe 
> I'm just less picky:-) And yes, in general I agree, I think, this level of 
> image quality tuning is difficult to achieve on modern cameras with 100s 
> of fine-tuning knobs. I'll try to re-test this camera in day light 
> conditions and post my best shot :)

http://download.open-technology.de/mt9m131/

.ppm is taken with mt9m131. Note, that I shot 10 frames and took the 3rd 
one - the first two are much darker, #3 is where autoexposure has kicked 
in, I suppose. Also note, that the comparison shot has been fired from a 
much smaller distance to cover a similar area due to obviously different 
lenses. I'll leave any colour-quality judgement to the reader(s) :-)

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: mt9m111/mt9m131: kernel 3.8 issues.

[javier Martin]

Hi Guennadi,

>> I just tested my mt9m131 camera on a i.MX31 board, if not this your email
>> I don't think I'd be alarmed by the image quality it's producing, maybe
>> I'm just less picky:-) And yes, in general I agree, I think, this level of
>> image quality tuning is difficult to achieve on modern cameras with 100s
>> of fine-tuning knobs. I'll try to re-test this camera in day light
>> conditions and post my best shot :)
>
> http://download.open-technology.de/mt9m131/
>
> .ppm is taken with mt9m131. Note, that I shot 10 frames and took the 3rd
> one - the first two are much darker, #3 is where autoexposure has kicked
> in, I suppose. Also note, that the comparison shot has been fired from a
> much smaller distance to cover a similar area due to obviously different
> lenses. I'll leave any colour-quality judgement to the reader(s) :-)

Thank you for your feedback. It seems that we all have a similar colour quality.
If Aptina comes up with better settings or I find them I'll post a
patch for you to test.

Regards.
-- 
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
www.vista-silicon.com