Ubuntu
xserver-xorg-driver-via package

  1. Bug #43154
  2. Comment #78

Comment 78 for bug 43154

Revision history for this message
In , Thomas-tungstengraphics (thomas-tungstengraphics) wrote :

Hi.

The IRQ issue on K8M800 has been around for ages. I'm not saying it can't be fixed (sometimes when my K8M800 has been running for quite some time it will work nicely), but trying to initialize it from scratch it always fails. The reason is that K8M800 fires a huge amount of spurious interrupts.

If irq debug is turned off, the handler slows down the machine considerably trying to handle the interrupts.

The problem is probably a hardware bug. The same problem occurs on certain variants of KM400. I once asked via about it and they claimed that IRQ functionality was never verified on these chips since they didn't do video capture. Hence no use for IRQs in VIAs windows drivers.

The only sane thing to do is to not enable IRQs for these chips.

Regarding the texture lockup issue,
the same code works much better on other chips with the same 3D engine.
It might just be a memory timing issue on K8M800, which means that tracking it down using software can be very difficult.

/Thomas