Why do I get purple stripes on my screen?

[hazel]

Sometimes when I boot up, instead of my login screen, I get a screenful of vertical purple stripes. There is a simple workaround: I just switch to a Linux virtual console and then back again. Sometimes I have to do it more than once but eventually the normal login widget appears. It happens with both gdm and slim.

I am curious to know what causes this behaviour. I have an Intel 82810 (CGC) Chipset Graphics Controller (rev 03).

[Rubberman]

Has it always done this, or is this a recent development? If recent, then I think your video controller is staring to fail. Your switching modes to fix it would indicate a correlation with the chip failure scenario.

[hazel]

It's happened on and off since I've had this machine, which is about two years now. I bought it second-hand. I haven't noticed the stripes getting any more frequent lately but your comment sounds ominous.

[Rubberman]

I could be a driver error also in that the possibility of a race condition in initializing the board is not being accounted for by the driver. Is the video built into the motherboard, or is it separate? If separate, what make+model is it? Since it has been more or less stable in behavior since you purchased the computer, then I think it is less likely that there is a hardware failure occuring.

[hazel]

It could be a driver error also in that the possibility of a race condition in initializing the board is not being accounted for by the driver. Is the video built into the motherboard, or is it separate?

It's an on-board chip.

Since it has been more or less stable in behaviour since you purchased the computer, then I think it is less likely that there is a hardware failure occuring.

Well, that's a relief! Like I said, it doesn't happen all that often. But what do you mean by "initialising the board"? I thought all hardware was initialised by the kernel at boot.