[Techteam] XO-1.5 Kernel Update (i.e My Weekly Status)

Mitch Bradley wmb at laptop.org
Mon Jul 20 12:40:04 EDT 2009

Deepak Saxena wrote:
>  simply grabbing that irq via request_irq() causes USB 
>   device insertion (and other things?) to break. 

I had a related problem in OFW - enabling the SMBALRT# pin (for DCON 
use) caused immediate wakeups from suspends (in OFW-based testing).  
OFW's solution is to enable SMBALRT# for the shortest possible time, 
just when it is being tested.

I wonder if a similar narrow-enable approach could be used with 
request_irq()?  I can see how that might be tricky.

Alternatively, could Linux avoid using interrupts for that DCON sync 
function, polling with interrupts disabled like OFW does?  The overall 
system performance impact should be small, since the maximum wait time 
is only one video frame, and it only happens a freeze points, which are 
presumably times of low activity.

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