On Thu, 1 Aug 2013, James Stone wrote: > I've got some error messages written to syslog now - with no audible > effect on audio processing: > Aug 1 01:12:36 blueberry kernel: [ 6233.028335] ehci-pci > 0000:00:12.2: iso underrun ffff8800c872db00 (1407+0 < 1471) That's an impressive one. It indicates no interrupts occurred during a period of at least (1471 - 1407)/8 = 8 ms! That should have produced an audible click, if you were listening at the right time and if a nonzero sound was playing. > Aug 1 01:12:36 blueberry kernel: [ 6233.028341] ehci-pci > 0000:00:12.2: iso underrun ffff88002e6f6800 (1392+7 < 1471) > Aug 1 01:12:36 blueberry kernel: [ 6233.028347] ehci-pci > 0000:00:12.2: iso underrun ffff8800b65b5e00 (1401+7 < 1471) ... > Aug 1 01:12:36 blueberry kernel: [ 6233.028462] ehci-pci > 0000:00:12.2: iso underrun ffff88002e6f6800 (1464+7 < 1472) These messages show the audio driver catching up. > Aug 1 01:12:36 blueberry kernel: [ 6233.028493] ehci-pci > 0000:00:13.2: iso underrun ffff8800c9fa6900 (2535+0 < 2606) I don't understand what happened here. The microframe number increased by 1134 from the preceding message, indicating that some 140 ms had elapsed, but the kernel's timestamp went up by only 30 us. Something is very wrong in your system. Maybe in the EHCI hardware, maybe in the BIOS firmware, maybe somewhere else. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
