On Tue, 8 Apr 2014, Russel Hughes wrote: > Hi, > > I put in a new kernel and get the response from uname -r of > 3.14.0-031400-generic, apologies for the pedantry I am not that sure > what I am doing. The device behaves exactly the same as default Linux > kernel, buffer is erratic not stable like USB 2.0 and audio droputs > every couple of seconds. The HDMI audio output does not work after > installing the new kernel. > > I captured some data with usbmon but its a big file 4MB so I can email > it separately if you are interested but a sample is as below.
Maybe it will help with the debugging if I point out that this usbmon trace definitely shows signs of something not working right. The URB completions for the isochronous-OUT endpoint are all delayed by 6 ms or so. Here's the first example: > ffff880036e15c00 2003753507 C Zo:2:003:1 0:1:1111:0 6 0:0:264 > 0:264:264 0:528:264 0:792:264 0:1056:264 1584 > > ffff880036e15c00 2003753516 S Zo:2:003:1 -115:1:1111 5 -18:0:264 > -18:264:264 -18:528:264 -18:792:264 -18:1056:264 1320 = 1537ea16 > c9e808b1 f60dd5f1 f7970801 e4fdef09 10fab104 f4e00afb c103fbf6 > ffff8800d0237600 2003753520 C Zi:2:003:1 0:1:1123:0 1 0:0:3 4 = 00030b00 The IN transfer was 1 frame long and scheduled for frame 1123, so its completion indicates that the current frame number is >= 1123. The OUT transfer was 6 frames long and scheduled for frame 1111, so it should have completed in frame 1117. But the timestamps show that the two URBs completed at the same time (only 13 us between them). Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
