[mythtv-users] Enabling IOMMU seems to have broken my tuners

[Mike Hodson]

On Mon, Jan 30, 2023 at 2:14 PM George Bingham <georgeb1962 at gmail.com>
wrote:

> On Sun, Jan 29, 2023 at 2:12 PM Gary Buhrmaster <gary.buhrmaster at gmail.com>
> wrote:
>
>> On Sat, Jan 28, 2023 at 2:24 AM Gary Buhrmaster
>> <gary.buhrmaster at gmail.com> wrote:
>>
>> The C206 chipset is a Xeon targeted chipset, and
>> the code in one of the possibly related drivers
>> mention some Xeon chipsets can be impacted,
>> with a likely error in the logs of the form:
>>     mpeg risc op code error
>>
>> If your card uses the cx23885 driver, try adding a
>>
>>    options cx23885 dma_reset_workaround=2
>>
>> to an appropriate modprobe.conf.d file (if it does
>> not help, remove it).
>>
>> Hi Gary,
>
> Hey, that worked!  Thank You, how in the heck did you figure that out??
>
> Anyway, glad you did, thank you!
>
>
Interesting results come back searching the dma_reset_workaround=2 flag for
cx23885, inclusive of this one older issue, that seems spot on.
https://github.com/b-rad-NDi/Ubuntu-media-tree-kernel-builder/issues/69#issuecomment-482776122
Also the original patch seems to be
https://github.com/b-rad-NDi/Ubuntu-media-tree-kernel-builder/issues/51

Mike
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