On Wed, 2005-02-02 at 11:30 -0500, Lee Revell wrote: > The ACPI/SMM Latency Problem > While testing the RT preemption patches we discovered that many, many > laptops are unsuitable for low latency audio work. > The laptops in question have a BIOS that implements ACPI via SMM. > According to AC this is a known broken design (in addition to audio, it > causes these systems to lose timer ticks with HZ=1000), but by his > estimate more than half of laptops have the problem. > > There is no 100% reliable way to tell if you have the ACPI/SMM problem. > If you need really low latency, in the mllisecond range, this is a > showstopper! So I think the best approach is for the Linux audio > community to create a "whitelist" of known good laptops. Wow, I'd heard about this SMM issue but didn't know it was so bad. I guess I'm lucky, I've been able to get ~6ms latency with USB. Dell Inspiron 5100. Completely coincidentally, this morning I was just thinking about the low latency wiki, and wondering if a whitelist would be a good addition. I also have some webspace to donate to such a cause. -ry -- Ryan Gallagher <ruinaudio@xxxxxxxxxxx>
