qt1010: Fix tuner frequency selection for 546 to 578 MHz range

The patch fixes frequency selection for some UHF frequencies e.g. channel 32 (562 MHz) on the qt1010 tuner. For those in the UK, this now means they can tune to the BBC channels (tested on a Compro Vista T750F).

One example of problem reports of the bug this fixes can be read at
http://www.freak-search.com/de/thread/330303/linux-dvb_tuning_problem_with_some_frequencies_qt1010,_dvb

Based on an original patch by Jyrki Kuoppala<[email protected]>

Signed-off-by Carlos Corbacho<[email protected]>

Cc Jyrki Kuoppala<[email protected]>

Cc Mauro Carvalho Chehab<[email protected]>

---
  drivers/media/common/tuners/qt1010.c |    3 ++-
  1 files changed, 2 insertions(+), 1 deletions(-)

drivers/media/common/tuners/qt1010.c +2 -2

index 9f5dba2..8c57d8c 100644
@@ -200,7 +200,8 @@ static int qt1010_set_params(struct dvb_frontend *fe,
  	if      (freq<  450000000) rd[15].val = 0xd0; /* 450 MHz */
  	else if (freq<  482000000) rd[15].val = 0xd1; /* 482 MHz */
  	else if (freq<  514000000) rd[15].val = 0xd4; /* 514 MHz */
-	else if (freq<  546000000) rd[15].val = 0xd7; /* 546 MHz */
+	else if (freq<  546000000) rd[15].val = 0xd6; /* 546 MHz */
+	else if (freq<  578000000) rd[15].val = 0xd8; /* 578 MHz */
  	else if (freq<  610000000) rd[15].val = 0xda; /* 610 MHz */
  	else                       rd[15].val = 0xd0;
 
 
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Hello,
You can try to fix it like that, but it is not proper way. It is kinda of hack which can just work or not. Proper way is to fix that tuner driver correctly and if it was used with zl10353 demoed fix that driver too to support IIRC IF/RF agc settings.

regards
Antti

Quoted 38 lines · Carlos Corbacho

The patch fixes frequency selection for some UHF frequencies e.g. channel 32 (562 MHz) on the qt1010 tuner. For those in the UK, this now means they can tune to the BBC channels (tested on a Compro Vista T750F).

One example of problem reports of the bug this fixes can be read at
http://www.freak-search.com/de/thread/330303/linux-dvb_tuning_problem_with_some_frequencies_qt1010,_dvb

Based on an original patch by Jyrki Kuoppala<[email protected]>

Signed-off-by Carlos Corbacho<[email protected]>

Cc Jyrki Kuoppala<[email protected]>

Cc Mauro Carvalho Chehab<[email protected]>

---
  drivers/media/common/tuners/qt1010.c |    3 ++-
  1 files changed, 2 insertions(+), 1 deletions(-)

drivers/media/common/tuners/qt1010.c +2 -1

index 9f5dba2..8c57d8c 100644
@@ -200,7 +200,8 @@ static int qt1010_set_params(struct dvb_frontend 
 *fe,
      if      (freq<  450000000) rd[15].val = 0xd0; /* 450 MHz */
      else if (freq<  482000000) rd[15].val = 0xd1; /* 482 MHz */
      else if (freq<  514000000) rd[15].val = 0xd4; /* 514 MHz */
-    else if (freq<  546000000) rd[15].val = 0xd7; /* 546 MHz */
+    else if (freq<  546000000) rd[15].val = 0xd6; /* 546 MHz */
+    else if (freq<  578000000) rd[15].val = 0xd8; /* 578 MHz */
      else if (freq<  610000000) rd[15].val = 0xda; /* 610 MHz */
      else                       rd[15].val = 0xd0;

Signature · 4 lines

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Hi,

To try and shed some more light into the issue, can you describe what the problem really is and how would we fix the driver correctly? By "work or not", do you mean the fix works with some devices but not with some other devices, with some received signal strengths but not some, or something else? Do you think there's a risk the fix will break something?

For me, without the fix, some of the major channels from the transmitter in the second largest city of Finland are missing, in other words the fix would remove a major showstopper. Based on Carlos's note, the situation in UK is something similar.

It's of course best to aim for the best possible fix, and if we have enough information to do that, that's of course preferable over this one. However, if there isn't enough information, and there's no risk of the proposed fix breaking something, perhaps this patch should be put in as an interim fix and add some notes somewhere that a better fix is preferable.

Jyrki

21.12.2011 09:26, Antti Palosaari kirjoitti:

Quoted 52 lines

Hello,
You can try to fix it like that, but it is not proper way. It is kinda of hack which can just work or not. Proper way is to fix that tuner driver correctly and if it was used with zl10353 demoed fix that driver too to support IIRC IF/RF agc settings.

regards
Antti

Quoted 40 lines · Carlos Corbacho

The patch fixes frequency selection for some UHF frequencies e.g. channel 32 (562 MHz) on the qt1010 tuner. For those in the UK, this now means they can tune to the BBC channels (tested on a Compro Vista T750F).

One example of problem reports of the bug this fixes can be read at
http://www.freak-search.com/de/thread/330303/linux-dvb_tuning_problem_with_some_frequencies_qt1010,_dvb

Based on an original patch by Jyrki Kuoppala<[email protected]>

Signed-off-by Carlos Corbacho<[email protected]>

Cc Jyrki Kuoppala<[email protected]>

Cc Mauro Carvalho Chehab<[email protected]>

---
drivers/media/common/tuners/qt1010.c | 3 ++-

1 files changed, 2 insertions(+), 1 deletions(-)

drivers/media/common/tuners/qt1010.c +0 -0

index 9f5dba2..8c57d8c 100644
@@ -200,7 +200,8 @@ static int qt1010_set_params(struct dvb_frontend
 *fe,

if (freq< 450000000) rd[15].val = 0xd0; /* 450 MHz */ else if (freq< 482000000) rd[15].val = 0xd1; /* 482 MHz */ else if (freq< 514000000) rd[15].val = 0xd4; /* 514 MHz */
- else if (freq< 546000000) rd[15].val = 0xd7; /* 546 MHz */
+ else if (freq< 546000000) rd[15].val = 0xd6; /* 546 MHz */
+ else if (freq< 578000000) rd[15].val = 0xd8; /* 578 MHz */ else if (freq< 610000000) rd[15].val = 0xda; /* 610 MHz */ else rd[15].val = 0xd0;

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Thanks, apparently you mean the valptr setting if clauses in QT1010_RD and QT1010_M1 cases, if I understand you correctly you are saying code should be changed as in the diff below (after my signature).

The change has to with setting reg1f_init_val, reg20_init_val and reg25_init_val. To match with
http://linuxtv.org/wiki/index.php/Quantek_QT1010 , the registers are 31, 32 and 37 in decimal.

The patch sent by Carlos modifies how register 0x22 (register 34 in decimal) is set from the frequency. Carlos's patch is based on my patch which was based on the apparently incorrect (based on Carlos's feedback to my original patch, but see below, perhaps the assumption wasn't incorrect after all) assumption of linear relation between frequency and register 34 equals 0x22 value. So, basically Carlos removed the 0xd1 -> 0xd2 part of my patch.

When following frequency setting from the description at
http://linuxtv.org/wiki/index.php/Quantek_QT1010 , register 34 is set from freq_slot12 in the following manner:

* if reg5_1 is equal to 0x34
o if freq_slot12 is larger equal to 0xF0
+ if freq_slot12 is less equal to 0xFA
# write freq_slot12 minus 0x20 into freq_slot12
+ else
# write 0xDA into freq_slot12
o else
+ write 0xD0 into freq_slot12
o write freq_slot12 into tmp_var1
* else
o write 0xD0 into tmp_var1

* write tmp_var1 to tuner register 34

That does describe a linear correlation between freq_slot12 value and what is stored to register 34. 0xf0..0xfa are converted to 0xd0 .. 0xda which are also the values used in qt1010.c. But I can't find where freq_slot12 comes from (that's apparently in the incomplete part ofcalculate_parameter). So it's possible freq_slot12 is converted from the frequency non-linearly somewhere before it's used to set register
34. The current qt1010.c frequency to register 34 value conversion is non-linear and looks strange, setting 0xd1 where linearly setting the value would be 0xd2. But IIRC Carlos reported that changing it to 0xd2 (as in my original proposed patch) breaks some frequencies.

One possibility to try would be to test if the setting of reg 34 indeed should be linearly derived from frequency, however not 0xd0, 0xd2, 0xd4 etc. as in my original patch but instead try 0xd0, 0xd1, 0xd2, 0xd3 etc:

     if      (freq < 450000000) rd[15].val = 0xd0; /* 450 MHz */
     else if (freq < 466000000) rd[15].val = 0xd1; /* 466 MHz */
     else if (freq < 482000000) rd[15].val = 0xd2; /* 482 MHz */
     else if (freq < 498000000) rd[15].val = 0xd3; /* 498 MHz */
     else if (freq < 514000000) rd[15].val = 0xd4; /* 514 MHz */
     else if (freq < 530000000) rd[15].val = 0xd5; /* 530 MHz */
     else if (freq < 546000000) rd[15].val = 0xd6; /* 546 MHz */
     else if (freq < 562000000) rd[15].val = 0xd7; /* 562 MHz */
     else if (freq < 578000000) rd[15].val = 0xd8; /* 578 MHz */

Carlos, can you try this, if this makes all channels work for you? According to my reasoning, this could be the proper patch, as the 0xd1 -> 0xd2 change in my original patch failed for you. This would fit the picture if your frequency is between 450 Mhz and 466 Mhz, in which case my patch changes the correct 0xd1 to the incorrect 0xd2.

If the test succeeds and the relation indeed is linear, instead of the table we'll the conversion with math, it's of course silly to have a table for a linear relation.

Going through this makes me wonder if we perhaps have two separate issues here - one problem with frequency setting experienced by me & Carlos, and another problem with tuner init & AGC which Antti is describing. Antti, can you comment if you think this may be the case? Or is the register 31,32&37 setting somehow related to frequency selection? Just wondering why the frequency table seems to fix the issue that me & Carlos and others are seeing, if the problem is somewhere else as Antti is saying. Two separate issues could explain this.

Antti, any pointers / more info on what's the problem with drivers/media/dvb/frontends/zl10353.c AGC settings and how to fix those settings?

Jyrki

diff -ur linux-3.0.3.orig/drivers/media/common/tuners/qt1010.c linux-3.0.3/drivers/media/common/tuners/qt1010.c
--- linux-3.0.3.orig/drivers/media/common/tuners/qt1010.c

2011-08-17 20:57:16.000000000 +0300

+++ linux-3.0.3/drivers/media/common/tuners/qt1010.c 2011-12-21
10:38:46.089650261 +0200

(quoted diff) +3 -3

@@ -371,16 +372,16 @@
                                               i2c_data[i].val);
                         break;
                 case QT1010_RD:
-                       if (i2c_data[i].val == 0x20)
+                       if (i2c_data[i].reg == 0x20)
                                 valptr = &priv->reg20_init_val;
                         else
                                 valptr = &tmpval;
                         err = qt1010_readreg(priv, i2c_data[i].reg,
 valptr);
                         break;
                 case QT1010_M1:
-                       if (i2c_data[i].val == 0x25)
+                       if (i2c_data[i].reg == 0x25)
                                 valptr = &priv->reg25_init_val;
-                       else if (i2c_data[i].val == 0x1f)
+                       else if (i2c_data[i].reg == 0x1f)
                                 valptr = &priv->reg1f_init_val;
                         else

                                 valptr = &tmpval;

21.12.2011 10:19, Antti Palosaari kirjoitti:

Quoted 99 lines

Moikka Jyrki & all.
If you look qt1010_init() you can see some registers are stored wrongly. There is compares that stores register values when .val is given. As you can see easily, it should store those when .reg is correct. Store register 0x25 when it is register 0x25 not register value. That leads calibration wrong => tuner sensitivity is bad. But if you fix that it will not likely work since ZL10353 demod AGC settings are not correct. So you should fix it too.

I hope you will fix that, since it is surely 10th time I am explaining that same story for someone :-(

t. Antti

Quoted 79 lines · Jyrki Kuoppala

Hi,

To try and shed some more light into the issue, can you describe what the problem really is and how would we fix the driver correctly? By "work or not", do you mean the fix works with some devices but not with some other devices, with some received signal strengths but not some, or something else? Do you think there's a risk the fix will break something?

For me, without the fix, some of the major channels from the transmitter in the second largest city of Finland are missing, in other words the fix would remove a major showstopper. Based on Carlos's note, the situation in UK is something similar.

It's of course best to aim for the best possible fix, and if we have enough information to do that, that's of course preferable over this one. However, if there isn't enough information, and there's no risk of the proposed fix breaking something, perhaps this patch should be put in as an interim fix and add some notes somewhere that a better fix is preferable.

Jyrki

21.12.2011 09:26, Antti Palosaari kirjoitti:

Quoted 53 lines

Hello,
You can try to fix it like that, but it is not proper way. It is kinda of hack which can just work or not. Proper way is to fix that tuner driver correctly and if it was used with zl10353 demoed fix that driver too to support IIRC IF/RF agc settings.

regards
Antti

Quoted 41 lines · Carlos Corbacho

The patch fixes frequency selection for some UHF frequencies e.g. channel 32 (562 MHz) on the qt1010 tuner. For those in the UK, this now means they can tune to the BBC channels (tested on a Compro Vista T750F).

One example of problem reports of the bug this fixes can be read at
http://www.freak-search.com/de/thread/330303/linux-dvb_tuning_problem_with_some_frequencies_qt1010,_dvb

Based on an original patch by Jyrki Kuoppala<[email protected]>

Signed-off-by Carlos Corbacho<[email protected]>

Cc Jyrki Kuoppala<[email protected]>

Cc Mauro Carvalho Chehab<[email protected]>

---
drivers/media/common/tuners/qt1010.c | 3 ++-

1 files changed, 2 insertions(+), 1 deletions(-)

drivers/media/common/tuners/qt1010.c +0 -0

index 9f5dba2..8c57d8c 100644
@@ -200,7 +200,8 @@ static int qt1010_set_params(struct dvb_frontend
 *fe,

if (freq< 450000000) rd[15].val = 0xd0; /* 450 MHz */ else if (freq< 482000000) rd[15].val = 0xd1; /* 482 MHz */ else if (freq< 514000000) rd[15].val = 0xd4; /* 514 MHz */
- else if (freq< 546000000) rd[15].val = 0xd7; /* 546 MHz */
+ else if (freq< 546000000) rd[15].val = 0xd6; /* 546 MHz */
+ else if (freq< 578000000) rd[15].val = 0xd8; /* 578 MHz */ else if (freq< 610000000) rd[15].val = 0xda; /* 610 MHz */ else rd[15].val = 0xd0;

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