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

[Ken Smith <kens999@gmail.com>]

Apologies for multiple posts - e-mail configuration error at my end.


Ken Smith wrote:
>
>
> 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 on 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 many PCIe cards do, as the quadHD card 
> discussed above. The HVR5525 is a dual DVB-T2/DVB-S2 card.
>
> Elsewhere I read about the dma_reset_workaround option. That option 
> did not appear to be in the driver included in standard kernel in 
> Rocky 8.5. I have tested with a 5.4 & 5.18 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 aborted recordings. Although the card does appear to recover, not 
> requiring a reboot/cold restart.
>
> I've also logged this on Bugzilla. For some reason my original 
> subscription to this list had stopped working so I may have missed 
> some threads since Oct 2020.
>
> I'd appreciate some assistance with this. What information can I 
> provide, or testing can I do, to help to trace this.
>
> Many thanks
>
> Ken
>
>