On Fri, 2005-04-01 at 23:05 -0800, Pallipadi, Venkatesh wrote: > It can be SMI happening in the platform. Typically BIOS uses some SMI > polling > to handle some devices during early boot. Though 500 microseconds sounds > a > bit too high. >
Nope, that sounds just about right. Buggy BIOSes that implement ACPI via SMM (or so I have been told) can stall the machine for over a millisecond, this is why some laptops lose timer ticks at HZ=1000. The issue is well known by Linux audio users, as it causes big problems for people who buy laptops for live audio use. A list of known good/bad machines would be a tremendous help, but no one knows the exact extent of the problem. All Acer laptops seem to be affected. Hardware manufacturers (laptops anyway) don't seem to care about anything below 1-2ms because Windows uses HZ=100 and the ASIO drivers on that platform only go down to about ~1.5 ms latency. Lee - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
