Re: further issues with MGA G200 graphics chipset

[Jacob Keller]

On 4/22/2026 5:05 PM, David Airlie wrote:
>>
>> These all appear to be workqueue warnings about functions that are
>> hogging CPU. If I look carefully, it looks like they are all possibly
>> related to the same mgag200 driver. At the very least
>> output_poll_execute is certainly related to the mgag200 stall.
>>
>> I do noot understand exactly what is causing the driver to get stuck,
>> its something in the i2c routine for reading the EDID block.
>>
>> I also see this being printed:
>>
>>  EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
>>
>> It appears to print quite consistently every few seconds. I guess this
>> might be possibly related to a bad EDID block on the mgag200 device?
>> What does this even mean?
>>
> 
> It sounds like the polling is having trouble with the i2c bus even if
> there is no cable plugged in, probably cheaped out on some pull
> up/down resistors on the VGA connector.
> 
> does adding drm_kms_helper.poll=0 help to the command line help?
> 
> Dave.
> 
This looks like it is a global parameter for all users of the
drm_kms_helper. Would it be feasible to have a mgag200 specific
parameter made available?

I am testing this out now, but if it helps, it would be good to be able
to disable polling only for mgag200 in the off chance that some system
has another device which depends on its functionality? I guess that may
not be super common so maybe its not a big deal...

Thanks,
Jake