[ivtv-users] Tinny Audio problem on ivtv 1.0.3
Kevin Blair
kaziya at experimental-networks.org
Fri Jul 4 04:27:46 CEST 2008
Andy Walls wrote:
> On Wed, 2008-07-02 at 11:25 -0300, Kevin Blair wrote:
>> Ok correction on modules in usage,
>> with the 2.6.25 kernel and bleeding edge driver the modules used are as
>> fallows:
>> # lsmod
>> Module Size Used by
>> tuner_simple 11600 1
>> tuner_types 13376 1 tuner_simple
>> tda9887 8964 1
>> tda8290 11652 0
>> wm8775 4844 0
>> cx25840 22988 0
>> tuner 21512 0
>> ivtv 115812 0
>> videodev 29248 2 tuner,ivtv
>> v4l1_compat 11844 1 videodev
>> firmware_class 6400 2 cx25840,ivtv
>> compat_ioctl32 896 1 ivtv
>> cx2341x 9476 1 ivtv
>> v4l2_common 8448 5 wm8775,cx25840,tuner,ivtv,cx2341x
>> tveeprom 10436 1 ivtv
>>
>> and on the 2.6.23 kernel with internal modules loaded it lsmod is:
>> # lsmod
>> Module Size Used by
>> wm8775 4684 0
>> cx25840 21712 0
>> ivtv 112080 0
>> firmware_class 6784 2 cx25840,ivtv
>> cx2341x 10052 1 ivtv
>> tveeprom 13456 1 ivtv
>>
>> i was looking on the wrong system and it didnt have the cx25840 module
>> loaded.
>
> Under 2.6.23 you don't have the tuner modules loaded. Without those
> loaded you may not have SIF coming out of the tuner to cause the audio
> microcontroller firmware to try and react to SIF audio changes and
> change audio settings. That could explain why 2.6.23 is not giving you
> problems. Or are your tuner drivers built into the kernel under your
> 2.6.23 configuration (invaliding my above train of thought)?
>
the tuner should be loaded, i know it was before because the 23kernel on
the slave was setup before i installed sat to tune to cable tv and was
never changed, after checking the config, the tuner seems to be built in
cat .config | grep TUNER
# CONFIG_TUNER_3036 is not set
# CONFIG_TUNER_TEA5761 is not set
CONFIG_VIDEO_TUNER=y
it looks like the ivtv option forces the tuner module to be built and
selects it as built in.
Kevin
>
>
>> as for the as of 30 min ago, bleeding edge driver the changes did not
>> resolve the tinny audio issue.
>
> I didn't think they would. Sorry if I caused confusion talking about
> how the firmware load of the cx28543 core for the cx18 driver was fixed.
> I am unaware of any modifications being made for the cx28540 driver
> loading firmware.
>
>
> I won't be answering email until at least Monday or Tuesday. Good luck.
>
> Regards,
> Andy
>
>> Kevin
>>
>> Andy Walls wrote:
>>> On Wed, 2008-07-02 at 01:20 -0300, Kevin Blair wrote:
>>>> well i did a simpler test, since i know that with the 2.6.25 kernel
>>>> driver or bleeding edge driver i get the bad audio, and i have moved the
>>>> testing to my slave system which is not dependant on running a 2.6.25
>>>> kernel i backsteped it to a 2.6.23 kernel it was previously running, and
>>>> the ivtv driver from that kernel, and i have not bin able to recreate
>>>> the tinny audio issue(after for going in and out of live tv for over
>>>> half an hour and no issue i dont think it will happen because usually i
>>>> can get the tinny audio in 5 min of testing), the only thing that has
>>>> changed is kernel and ivtv driver, all i did was boot it up on the old
>>>> build of the 2.6.23 kernel which used the old setup on the slave (before
>>>> i built the 2.6.25 kernel and installed the bleeding edge driver) so it
>>>> would appear that something that changed since the 2.6.23 kernel driver
>>>> which is causing this, correct me if im wrong.
>>> Overall, I cannot say you are wrong, you have found a causal
>>> relationship.
>>>
>>> The question is where is the problem: the ivtv driver, the cx28540
>>> module, the i2c drivers, or the firmware image request process? (Doing
>>> a great big recursive diff of the kernel and driver source code would
>>> show you what's changed, but maybe not easily show what the problem is.)
>>>
>>> It still appears to be audio microcontroller related to me. I am
>>> unaware of anything else that could regularly tries to change the audio
>>> settings in the cx28543 chip (unless a user application is requesting it
>>> - maybe turn on ioctl debugging in ivtv to see). And since resetting
>>> that microcontroller makes the problem go away, it really stands out as
>>> an actor in the problem.
>>>
>>> Hans just made a fix to the firmware download to the AV core in the
>>> CX23418 for the cx18 driver (it has a very similar core and firmware to
>>> the CX28543). He noted that the firmware download had byte errors by
>>> doing read backs of the bytes just written to the chip. If something
>>> changed that introduces byte errors in the download of firmware to the
>>> cx28540, that could obviously cause the audio microcontroller firmware
>>> to act funny.
>>>
>>>
>>> You've found a causal relationship, but the root cause is still unknown.
>>> To find the root cause, I can only think of two methodologies:
>>> inspection and analysis of the differences between the source code
>>> version (likely a big job but it is a deterministic process), or making
>>> some hypotheses and testing those hypotheses (smaller jobs but not
>>> guaranteed to provide an answer).
>>>
>>> Regards,
>>> Andy
>>>
>>>> Kevin
>>>>
>>>> Andy Walls wrote:
>>>>> On Tue, 2008-07-01 at 01:34 -0300, Kevin Blair wrote:
>>>>>> i dont be leave it produced the tinny audio before, but
>>>>>> several things have changed (went from coax to svideo/rca input,
>>>> since i cannot remember for the life of me the detail but the more i
>>>> think about it im sure it was working fine and since on the slave
>>>> downgrading fixes it, so i took a step back looked at the history i
>>>> have, being i had the master system built since the beginning of march
>>>> and did not have any issues with audio but i did have issues with
>>>> sata_mv which i upgraded from a 2.6.24 kernel to a 2.6.25 kernel when it
>>>> became stable at the beginning of may, so for almost 2 months it was
>>>> running fine, based on the time i had it built and running and the time
>>>> i upgraded to the .25 kernel, and few days after i installed the .25
>>>> kernel i was posting on the board with the issue. so it must be one of
>>>> the changes from the 2.6.24 and the 2.6.25 kernel that is causing it.
>>>>
>>>>> Kevin,
>>>>>
>>>>> That is an interesting bit of information. So here's a new hypothesis:
>>>>>
>>>>> The audio micontroller firmware is changing the digital audio baseband
>>>>> processing settings in the CX28543, corrupting the settings for line in
>>>>> audio, when it thinks it detects a TV audio standard change coming in
>>>>> from the tuner SIF audio input.
>>>>>
>>>>> If that is true, then simple solutions could be
>>>>>
>>>>> 1. stop the audio standard detection microcontroller firmware from
>>>>> running when you've switched to an audio input other than the tuner.
>>>>>
>>>>> or
>>>>>
>>>>> 2. connect an RF TV signal source to the tuner and tune the card to an
>>>>> active TV station before making the switch to the svideo or composite
>>>>> input.
>>>>>
>>>>>
>>>>>
>>>>> #2 is something you can try on your own to see if it eliminates the
>>>>> tinny audio.
>>>>>
>>>>> #1 you can try manually by commanding the ivtv driver to switch to the
>>>>> line in input and then stopping the audio microcontroller by setting bit
>>>>> 4 (bit 0 is the lsb, bit 7 is the msb) of register 0x803 of the CX28543
>>>>> to 0 with v4l2-dbg. v4l2-ctl --log-status will then show the audio
>>>>> microcontroller as stopped. When the audio microcontroller is stopped,
>>>>> nothing should be automatically changing the processing of input audio.
>>>>>
>>>>> The problem with doing #1, is that it takes quite a few steps to get the
>>>>> audio microcontroller started properly again, and it's probably not a
>>>>> good idea to try it manually. If you can verify that stopping the audio
>>>>> microcontroller after switching to non-tuner inputs solves the onset of
>>>>> tinny audio, then work can be done on the cx28540 driver to incorporate
>>>>> this solution.
>>>>>
>>>>> Regards,
>>>>> Andy
>>>>>
>>>>>> Kevin
>>>>>
>
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