Auckland Testing Summary 23 March 2013

Tom Parker tom at
Mon Mar 25 15:09:10 EDT 2013

On 24/03/13 17:56, Gary Martin wrote:
>> Physics still has the top of screen problem on XO-1.75 but is working very well on XO-4.
> How critical do you think this one is?

It's quite annoying if you happen to build something in physics that 
extends to the top of the screen and certainly doesn't look good when 
you show people the laptop.

> I have a patch from John that fixes this, it's related to hardware driver frame buffer support issues, but at the cost of some memory & performance cycles. Basically it removes pygame default screen buffering feature and does the buffering manually – no more white flicker at the top of the XO-1.75 redraw cycle, but not for free.

Is this as a workaround for a bug in pygame and/or the graphics drivers? 
Can you isolate the change to XO-1.75 only? The other hardware seems to 
work fine and doesn't need a performance hit.

Are you able to synchronize with the vertical blanking interrupt? I once 
wrote a hack for an Amiga with an add-on graphics card that didn't drive 
the vertical blank interrupt to busy wait until the vertical blank 
started. It had a timer and kept the busy wait period small but not so 
small that it would miss the start of the vblank.. This stopped icons 
flickering when you dragged them.

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