Re: HauppaugeTV-quadHD DVB-T & HVR5525 mpeg risc op code error

[Ken Smith <kens@kensnet.org>]

(Resend - first send did not reach the list  )


Ian Young wrote:
> On Tue, Apr 28, 2020 at 08:24:20PM +0200, Martin Burnicki wrote:
>> Hi,
>>
>> Am 27.04.20 um 10:59 schrieb Martin Burnicki:
>>> Sean Young wrote:
>>>> Would you mind testing this patch please?
>>> I'm going to try it this evening.
>>>
>>> I'll have to find out how to do an out-of-tree build for a copy of the
>>> cx module that includes the patch.
>>>
>>> My own kernel driver is always and only built out-of-tree, but for the
>>> cx driver I need to see which files I need to copy to a local directory,
>>> and if there is anything else that needs to be done to build a copy of
>>> it out-of-tree.
>> Sorry, I haven't managed to test the patch, yet.
>>
>> Currently I have the driver loaded with
>>
>> options cx23885 dma_reset_workaround=2
>>
>> but today there were 3 occurrences of the risc opcode error:
>>
>>
> Drats.
>
>> So the workaround doesn't seem to fix the problem anyway, and the patch
>> would just enable the workaround with out the specific option, right?
> Yes, that's right.
>
>> The effect of the workaround looks just like debug levels lower than 7,
>> it just seems to reduce the probability that the bug occurs, but doesn't
>> really fix it.
>>
>> So my conclusion is still that that this smells like a missing memory
>> barrier or so in the driver.
>>
>> Since the driver seems to work properly with older mainboards/CPU types,
>> this doesn't sound like a problem in the CX chip, IMO.
> I would agree with that. I would suspect same issue was being papered over
> by the patch; now what that issue is, I don't know. Certainly some 
> ordering
> or barrier issue seems likely.
>
> Actually I suspected this all along, but the workaround is the best we 
> have.
>
> I think, some time spent hunting down the issue would really be helpful
> here. Hopefully that doesn't mean too many aborted recordings..
>
> Thanks,
>
> Sean
>

Hi, I'd like to resurrect this thread (copied above). I have a system 
showing this error. Its a HP ML350 server with 2x Xeon 5675 running 
Rocky Linux 8.5. It has a Hauppauge HVR5525 card that uses the same 
cx23885 kernel module as the quadHD card discussed above. The HVR5525 is 
a dual DVB-T2/DVB-S2 card.

In other threads I read about the dma_reset_workaround option. That 
option did not appear to be in the version included in standard kernel 
in Rocky 8.5. I have loaded a 5.4 kernel and compiled the DVB media 
modules from .git source and set dma_reset_workaround=2 in a file in 
modprobe.d. The built module shows version 0.0.4

Sadly the error remains. The system runs MythTV v.31. The main symptom 
is occasional aborted recordings. Although the card does appear to 
recover, not requiring a reboot/cold restart.

I'd appreciate some assistance with this. What information can I provide 
to help to trace this.

Many thanks

Ken


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