Re: further issues with MGA G200 graphics chipset

[Thomas Zimmermann]

Hi Jocelyn

Am 24.04.26 um 09:36 schrieb Jocelyn Falempe:
> On 24/04/2026 08:20, Thomas Zimmermann wrote:
> > Hi
> >
> > Am 23.04.26 um 21:42 schrieb Jacob Keller:
> > [...]
> > > Unfortunately, I also have no better idea than a DMI quirk table to
> > > record known platforms that include the controller but don't have a
> > > physical VGA connection exposed.
> >
> > I'm in favor of this. If you send a meaningful DMI identifier for 
> > your system, I'd make you a patch for testing.
>
> I didn't find something related to VGA connector in dmidecode.
> My suggestion would be to use the chassis-type [1], and disable 
> polling on Blade (0x1C and 0x1D) and Rack Mount (0x17) as they are 
> less likely to have a real VGA monitor connected.
> My Dell T310, which is kind of a Tower, has a chassis-type of 0x11 
> "Main server chassis" so it might not be very reliable.

This is the first time, I hear about this problem. I don't think it's 
very common. And it appears only to be related due to cheap hardware 
manufacturing.

So I suggest to pick Manufacturer, Product, Version as key. I'd be 
surprised if we find more than a hand full of systems with the issue. If 
we see a trend or common pattern, we can generalize later on.


> Another option would be to disable polling if PREEMPT_RT is set, so if 
> the user expects low latency, he can actually have it.
>
> Last resort is that the driver did work for 2 decades without polling 
> the VGA connector, maybe we can revert to that behavior.

It didn't actually work. Removing it will break a lot of systems.

Best regards
Thomas


--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)