Throw this one in the running for strangest bug ever: For some reason, on 2.6.17-2.6.19(+others?) the acpi_processor_idle loop enabled by CONFIG_ACPI_PROCESSOR is causing my laptop's speakers to buzz.. If the option is disabled or built as a module (or if I run both my CPUs' usage up to 100%), the speakers are silent. I drilled a little further down, and it seems to have something to do with the busmastering code. If I hack drivers/acpi/processor_core.c to always set bm_control = 0, the whine goes away. Of course, disabling bustmastering disables all C2 to C3 transitions, so maybe it is an unrelated matter still.. Another datapoint: If I boot into single user mode, I can get an (almost) silent mode of operation by removing uhci_ocd, or if I turn off bluetooth via the switch on my laptop. However, other drivers are involved in the buzz as well because if I do a full boot, killing USB+bluetooth does not help. proc is telling me the latency value for C3 is 57. To see if it was perhaps rapid state transitions, I tried doubling the threshold.count values for every state. Didn't seem to change the pitch or volume of the whine... So, any ideas? Is this a bug in linux-acpi, or my laptop's ACPI support? Any way to tell? Windows doesn't whine, but Linux in VMware in Windows does (again, only if the CPU is idle). -- Mike Perry Mad Computer Scientist fscked.org evil labs - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
