On Wed, Jul 31, 2013 at 10:07 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 31 Jul 2013, James Stone wrote: > >> On Wed, Jul 31, 2013 at 4:48 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> > On Tue, 30 Jul 2013, Alan Stern wrote: >> > >> >> I can try to ameliorate the situation. Although the 7-ms delay will >> >> inevitably cause an underrun, it doesn't have to cause errors the way >> >> it does now. I'll write a patch to handle this. It may take a few >> >> days. >> > >> > James, see what happens with this patch. It will print a warning >> > message in the system log every time it detects an underrun, but it >> > won't cause an URB submission failure any more. >> > >> >> OK - I will try it, however, it seems a bit like papering over the >> cracks without really understanding what's causing the error.. > > It seems likely that the error is caused by an SMI taking too much > time. At least, we seem to have ruled out everything else. Besides, > this change has to be made eventually in any case -- underruns can > occur at any time, in principle, and they shouldn't cause the audio > driver to fail. > > By the way, can you post the contents of /proc/interrupts? I'd like to > see if the IRQ line in question is shared. > >> I just managed to induce another cannot submit URB bug, and there is >> definitely nothing written to trace around the time of this bug, with >> the settings: >> >> echo 0 > options/function-trace >> echo irqsoff > current_tracer >> echo 1 > tracing_on >> echo 0 > tracing_max_latency > > You may need to do "echo 0 >tracing_on" before looking at the file. > I'm not sure. > > But the tracer certainly should contain _something_, because interrupts > are constantly being disabled and enabled during normal system > operation. Even if nothing went wrong, there would still be a nonzero > latency. > > Alan Stern > I've got some error messages written to syslog now - with no audible effect on audio processing: Aug 1 01:12:36 blueberry kernel: [ 6233.016246] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7600 (1360+7 < 1374) Aug 1 01:12:36 blueberry kernel: [ 6233.016275] retire_capture_urb: 27 callbacks suppressed Aug 1 01:12:36 blueberry kernel: [ 6233.016287] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6700 (2503+0 < 2509) Aug 1 01:12:36 blueberry kernel: [ 6233.028335] ehci-pci 0000:00:12.2: iso underrun ffff8800c872db00 (1407+0 < 1471) 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: [ 6233.028350] ehci-pci 0000:00:12.2: iso underrun ffff88002df88800 (1415+0 < 1471) Aug 1 01:12:36 blueberry kernel: [ 6233.028355] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7000 (1400+7 < 1471) Aug 1 01:12:36 blueberry kernel: [ 6233.028361] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b4600 (1409+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028364] ehci-pci 0000:00:12.2: iso underrun ffff8800c9c93600 (1423+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028369] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7600 (1408+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028374] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b4800 (1417+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028377] ehci-pci 0000:00:12.2: iso underrun ffff8800c9c93f00 (1431+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028382] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f6800 (1416+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028387] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b4200 (1425+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028390] ehci-pci 0000:00:12.2: iso underrun ffff8800c872db00 (1439+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028395] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7000 (1424+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028400] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b5e00 (1433+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028404] ehci-pci 0000:00:12.2: iso underrun ffff88002df88800 (1447+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028409] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7600 (1432+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028415] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b4600 (1441+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028418] ehci-pci 0000:00:12.2: iso underrun ffff8800c9c93600 (1455+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028424] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f6800 (1440+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028429] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b4800 (1449+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028432] ehci-pci 0000:00:12.2: iso underrun ffff8800c9c93f00 (1463+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028438] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7000 (1448+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028443] ehci-pci 0000:00:12.2: iso underrun ffff8800b65b4200 (1457+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028446] ehci-pci 0000:00:12.2: iso underrun ffff8800c872db00 (1471+0 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028452] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f7600 (1456+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028462] ehci-pci 0000:00:12.2: iso underrun ffff88002e6f6800 (1464+7 < 1472) Aug 1 01:12:36 blueberry kernel: [ 6233.028493] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6900 (2535+0 < 2606) Aug 1 01:12:36 blueberry kernel: [ 6233.028498] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6800 (2543+0 < 2606) Aug 1 01:12:36 blueberry kernel: [ 6233.028502] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6700 (2551+0 < 2606) Aug 1 01:12:36 blueberry kernel: [ 6233.028507] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6900 (2559+0 < 2606) Aug 1 01:12:36 blueberry kernel: [ 6233.028511] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6800 (2567+0 < 2606) Aug 1 01:12:36 blueberry kernel: [ 6233.028515] ehci-pci 0000:00:13.2: iso underrun ffff8800c9fa6700 (2575+0 < 2606) James -- 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
