Re: [PATCH 0/1] xc3028: fix center frequency calculation for DTV78 firmware

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On 10-12-2011 16:01, Gianluca Gennari wrote:
Il 10/12/2011 15:51, Mauro Carvalho Chehab ha scritto:
On 08-12-2011 10:56, Gianluca Gennari wrote:
Hi all,
this patch replaces the previous one proposed in the thread "xc3028:
force reload of DTV7 firmware in VHF band with Zarlink demodulator".
The problem is that the firmware DTV78 works fine in UHF band (8 MHz
bandwidth) but is not working at all in VHF band (7 MHz bandwidth).
Reading the comments inside the code, I figured out that the real
problem could be connected to the formula used to calculate the center
frequency offset in VHF band.

In fact, removing this adjustment fixed the problem:

         if ((priv->cur_fw.type&   DTV78)&&   freq<   470000000)
             offset -= 500000;

This is coherent to what was implemented for the DTV7 firmware by an
Australian user:

         if (priv->cur_fw.type&   DTV7)
             offset += 500000;

In the end, the center frequency is the same for all firmwares (DTV7,
DTV8, DTV78) and for both 7 and 8 MHz bandwidth.
Probably, a further offset is hardcoded directly into the firmwares, to
compensate the difference between 7 and 8 MHz bandwidth.

The final code looks clean and simple, and there is no need for any
"magic" adjustment:

         if (priv->cur_fw.type&   DTV6)
             offset = 1750000;
         else    /* DTV7 or DTV8 or DTV78 */
             offset = 2750000;


The above comment is better than the one inside the patch. Just add it
there
when submitting the final review.

Yet, I don't think this is right, at least for firmware 2.7 and bellow.

What happens with xc3028 devices is that the frequency of the DLL is set
to a
"reference" frequency, and not to the center frequency. The reference
frequency
is 1.25 MHz after the lower frequency.

The standard-specific firmwares could also have an extra offset, as well
as the
S-CODE tables. In general, the offset for them are 200 kHz, but it seems
that

Not sure if you're aware, but you can look on each firmware with an
userspace tool
that is part of v4l-utils:

~/v4l-utils/utils/xc3028-firmware $ ./firmware-tool --list
/lib/firmware/xc3028-v27.fw
list action

firmware file name: /lib/firmware/xc3028-v27.fw
firmware name:    xc2028 firmware
version:    2.7 (519)
standards:    80
Firmware  0, type: BASE FW   F8MHZ (0x00000003), id: (0000000000000000),
size: 8718
Firmware  1, type: BASE FW   F8MHZ MTS (0x00000007), id:
(0000000000000000), size: 8712
Firmware  2, type: BASE FW   FM (0x00000401), id: (0000000000000000),
size: 8562
Firmware  3, type: BASE FW   FM INPUT1 (0x00000c01), id:
(0000000000000000), size: 8576
Firmware  4, type: BASE FW   (0x00000001), id: (0000000000000000), size:
8706
Firmware  5, type: BASE FW   MTS (0x00000005), id: (0000000000000000),
size: 8682
Firmware  6, type: STD FW    (0x00000000), id: PAL/BG A2/A
(0000000100000007), size: 161
Firmware  7, type: STD FW    MTS (0x00000004), id: PAL/BG A2/A
(0000000100000007), size: 169
Firmware  8, type: STD FW    (0x00000000), id: PAL/BG A2/B
(0000000200000007), size: 161
Firmware  9, type: STD FW    MTS (0x00000004), id: PAL/BG A2/B
(0000000200000007), size: 169
Firmware 10, type: STD FW    (0x00000000), id: PAL/BG NICAM/A
(0000000400000007), size: 161
Firmware 11, type: STD FW    MTS (0x00000004), id: PAL/BG NICAM/A
(0000000400000007), size: 169
Firmware 12, type: STD FW    (0x00000000), id: PAL/BG NICAM/B
(0000000800000007), size: 161
Firmware 13, type: STD FW    MTS (0x00000004), id: PAL/BG NICAM/B
(0000000800000007), size: 169
Firmware 14, type: STD FW    (0x00000000), id: PAL/DK A2
(00000003000000e0), size: 161
Firmware 15, type: STD FW    MTS (0x00000004), id: PAL/DK A2
(00000003000000e0), size: 169
Firmware 16, type: STD FW    (0x00000000), id: PAL/DK NICAM
(0000000c000000e0), size: 161
Firmware 17, type: STD FW    MTS (0x00000004), id: PAL/DK NICAM
(0000000c000000e0), size: 169
Firmware 18, type: STD FW    (0x00000000), id: SECAM/K1
(0000000000200000), size: 161
Firmware 19, type: STD FW    MTS (0x00000004), id: SECAM/K1
(0000000000200000), size: 169
Firmware 20, type: STD FW    (0x00000000), id: SECAM/K3
(0000000004000000), size: 161
Firmware 21, type: STD FW    MTS (0x00000004), id: SECAM/K3
(0000000004000000), size: 169
Firmware 22, type: STD FW    D2633 DTV6 ATSC (0x00010030), id:
(0000000000000000), size: 149
Firmware 23, type: STD FW    D2620 DTV6 QAM (0x00000068), id:
(0000000000000000), size: 149
Firmware 24, type: STD FW    D2633 DTV6 QAM (0x00000070), id:
(0000000000000000), size: 149
Firmware 25, type: STD FW    D2620 DTV7 (0x00000088), id:
(0000000000000000), size: 149
Firmware 26, type: STD FW    D2633 DTV7 (0x00000090), id:
(0000000000000000), size: 149
Firmware 27, type: STD FW    D2620 DTV78 (0x00000108), id:
(0000000000000000), size: 149
Firmware 28, type: STD FW    D2633 DTV78 (0x00000110), id:
(0000000000000000), size: 149
Firmware 29, type: STD FW    D2620 DTV8 (0x00000208), id:
(0000000000000000), size: 149
Firmware 30, type: STD FW    D2633 DTV8 (0x00000210), id:
(0000000000000000), size: 149
Firmware 31, type: STD FW    FM (0x00000400), id: (0000000000000000),
size: 135
Firmware 32, type: STD FW    (0x00000000), id: PAL/I (0000000000000010),
size: 161
Firmware 33, type: STD FW    MTS (0x00000004), id: PAL/I
(0000000000000010), size: 169
Firmware 34, type: STD FW    (0x00000000), id: SECAM/L AM
(0000001000400000), size: 169
Firmware 35, type: STD FW    (0x00000000), id: SECAM/L NICAM
(0000000c00400000), size: 161
Firmware 36, type: STD FW    (0x00000000), id: SECAM/Lc
(0000000000800000), size: 161
Firmware 37, type: STD FW    (0x00000000), id: NTSC/M Kr
(0000000000008000), size: 161
Firmware 38, type: STD FW    LCD (0x00001000), id: NTSC/M Kr
(0000000000008000), size: 161
Firmware 39, type: STD FW    LCD NOGD (0x00003000), id: NTSC/M Kr
(0000000000008000), size: 161
Firmware 40, type: STD FW    MTS (0x00000004), id: NTSC/M Kr
(0000000000008000), size: 169
Firmware 41, type: STD FW    (0x00000000), id: NTSC PAL/M PAL/N
(000000000000b700), size: 161
Firmware 42, type: STD FW    LCD (0x00001000), id: NTSC PAL/M PAL/N
(000000000000b700), size: 161
Firmware 43, type: STD FW    LCD NOGD (0x00003000), id: NTSC PAL/M PAL/N
(000000000000b700), size: 161
Firmware 44, type: STD FW    (0x00000000), id: NTSC/M Jp
(0000000000002000), size: 161
Firmware 45, type: STD FW    MTS (0x00000004), id: NTSC PAL/M PAL/N
(000000000000b700), size: 169
Firmware 46, type: STD FW    MTS LCD (0x00001004), id: NTSC PAL/M PAL/N
(000000000000b700), size: 169
Firmware 47, type: STD FW    MTS LCD NOGD (0x00003004), id: NTSC PAL/M
PAL/N (000000000000b700), size: 169
Firmware 48, type: SCODE FW  HAS IF (0x60000000), IF = 3.28 MHz id:
(0000000000000000), size: 192
Firmware 49, type: SCODE FW  HAS IF (0x60000000), IF = 3.30 MHz id:
(0000000000000000), size: 192
Firmware 50, type: SCODE FW  HAS IF (0x60000000), IF = 3.44 MHz id:
(0000000000000000), size: 192
Firmware 51, type: SCODE FW  HAS IF (0x60000000), IF = 3.46 MHz id:
(0000000000000000), size: 192
Firmware 52, type: SCODE FW  DTV6 ATSC OREN36 HAS IF (0x60210020), IF =
3.80 MHz id: (0000000000000000), size: 192
Firmware 53, type: SCODE FW  HAS IF (0x60000000), IF = 4.00 MHz id:
(0000000000000000), size: 192
Firmware 54, type: SCODE FW  DTV6 ATSC TOYOTA388 HAS IF (0x60410020), IF
= 4.08 MHz id: (0000000000000000), size: 192
Firmware 55, type: SCODE FW  HAS IF (0x60000000), IF = 4.20 MHz id:
(0000000000000000), size: 192
Firmware 56, type: SCODE FW  MONO HAS IF (0x60008000), IF = 4.32 MHz id:
NTSC/M Kr (0000000000008000), size: 192
Firmware 57, type: SCODE FW  HAS IF (0x60000000), IF = 4.45 MHz id:
(0000000000000000), size: 192
Firmware 58, type: SCODE FW  MTS LCD NOGD MONO IF HAS IF (0x6002b004),
IF = 4.50 MHz id: NTSC PAL/M PAL/N (000000000000b700), size: 192
Firmware 59, type: SCODE FW  LCD NOGD IF HAS IF (0x60023000), IF = 4.60
MHz id: NTSC/M Kr (0000000000008000), size: 192
Firmware 60, type: SCODE FW  DTV6 QAM DTV7 DTV78 DTV8 ZARLINK456 HAS IF
(0x620003e0), IF = 4.76 MHz id: (0000000000000000), size: 192
Firmware 61, type: SCODE FW  HAS IF (0x60000000), IF = 4.94 MHz id:
(0000000000000000), size: 192
Firmware 62, type: SCODE FW  HAS IF (0x60000000), IF = 5.26 MHz id:
(0000000000000000), size: 192
Firmware 63, type: SCODE FW  MONO HAS IF (0x60008000), IF = 5.32 MHz id:
PAL/BG A2 NICAM (0000000f00000007), size: 192
Firmware 64, type: SCODE FW  DTV7 DTV78 DTV8 DIBCOM52 CHINA HAS IF
(0x65000380), IF = 5.40 MHz id: (0000000000000000), size: 192
Firmware 65, type: SCODE FW  DTV6 ATSC OREN538 HAS IF (0x60110020), IF =
5.58 MHz id: (0000000000000000), size: 192
Firmware 66, type: SCODE FW  HAS IF (0x60000000), IF = 5.64 MHz id:
PAL/BG A2 (0000000300000007), size: 192
Firmware 67, type: SCODE FW  HAS IF (0x60000000), IF = 5.74 MHz id:
PAL/BG NICAM (0000000c00000007), size: 192
Firmware 68, type: SCODE FW  HAS IF (0x60000000), IF = 5.90 MHz id:
(0000000000000000), size: 192
Firmware 69, type: SCODE FW  MONO HAS IF (0x60008000), IF = 6.00 MHz id:
PAL/DK PAL/I SECAM/K3 SECAM/L SECAM/Lc NICAM (0000000c04c000f0), size: 192
Firmware 70, type: SCODE FW  DTV6 QAM ATSC LG60 F6MHZ HAS IF
(0x68050060), IF = 6.20 MHz id: (0000000000000000), size: 192
Firmware 71, type: SCODE FW  HAS IF (0x60000000), IF = 6.24 MHz id:
PAL/I (0000000000000010), size: 192
Firmware 72, type: SCODE FW  MONO HAS IF (0x60008000), IF = 6.32 MHz id:
SECAM/K1 (0000000000200000), size: 192
Firmware 73, type: SCODE FW  HAS IF (0x60000000), IF = 6.34 MHz id:
SECAM/K1 (0000000000200000), size: 192
Firmware 74, type: SCODE FW  MONO HAS IF (0x60008000), IF = 6.50 MHz id:
PAL/DK SECAM/K3 SECAM/L NICAM (0000000c044000e0), size: 192
Firmware 75, type: SCODE FW  DTV6 ATSC ATI638 HAS IF (0x60090020), IF =
6.58 MHz id: (0000000000000000), size: 192
Firmware 76, type: SCODE FW  HAS IF (0x60000000), IF = 6.60 MHz id:
PAL/DK A2 (00000003000000e0), size: 192
Firmware 77, type: SCODE FW  MONO HAS IF (0x60008000), IF = 6.68 MHz id:
PAL/DK A2 (00000003000000e0), size: 192
Firmware 78, type: SCODE FW  DTV6 ATSC TOYOTA794 HAS IF (0x60810020), IF
= 8.14 MHz id: (0000000000000000), size: 192
Firmware 79, type: SCODE FW  HAS IF (0x60000000), IF = 8.20 MHz id:
(0000000000000000), size: 192

I did a quick check here with firmware v2.7. The standard firmwares for
DTV7 and DTV8 are equal.
The firmware for DTV78 has one byte with a different value. So, it seems
that the offset for
DVB7 should be different than the one for DVB8.

Regards,
Mauro



Hi Mauro,
thanks for the review and the info about the firmware tool.
The interesting thing is that DTV7 and DTV8 are identical: this means
there is no info about bandwidth coded inside them.

Yes.

Also, the SCODE table (firmware 60) is the same for all 3 firmware
types: in fact, this is what is loaded when selecting a VHF frequency,
just after a replug of my Terratec stick:

[ 8701.753768] xc2028 0-0061: Loading firmware for type=BASE F8MHZ MTS
(7), id 0000000000000000.
[ 8702.804153] xc2028 0-0061: Loading firmware for type=D2633 DTV7 (90),
id 0000000000000000.
[ 8702.819274] xc2028 0-0061: Loading SCODE for type=DTV6 QAM DTV7 DTV78
DTV8 ZARLINK456 SCODE HAS_IF_4760 (620003e0), id 0000000000000000.

and the, after selecting a UHF frequency:

[ 8758.361730] xc2028 0-0061: Loading firmware for type=D2633 DTV78
(110), id 0000000000000000.
[ 8758.376951] xc2028 0-0061: Loading SCODE for type=DTV6 QAM DTV7 DTV78
DTV8 ZARLINK456 SCODE HAS_IF_4760 (620003e0), id 0000000000000000.

Yes. Anyway, the driver uses only the IF criteria to select the scode
table.

So, if the center frequency is indeed the same in all cases, the
variable part could be the so called "reference frequency"; this
frequency could be 1.25 MHz for 8 MHz channels and 1.75 MHz for 7 MHz
channels.

Yes. If the firmware is the same, the change between 7MHz and 8MHz should
be done via the center frequency offset adjustment.


But those are just conjectures; maybe in the comment I should just
specify what I did and why I did it, removing the sentence with
"probably...".

Ok. I'll mark the current patch as RFC and wait for your next version.

Best regards,
Gianluca

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