On Monday 22 Jan 2018 15:40:03 Keith A. Milner wrote:
On Monday 22 Jan 2018 14:06:08 Keith A. Milner wrote:
On Wednesday 23 Aug 2017 14:52:43 Clemens Ladisch wrote:
Keith A. Milner wrote:
My next course of action is to try to work out why the sync endpoint doesn't seem to be opened.
Right, so I see it IS being opened, and this results in URB_ISOCHRONOUS in URBs being sent, and the device responds (packet dissection in attached files for alsa and windows). However, the sync packets received are empty and are, thus, ignored by snd_usb_handle_sync_urb (in endpoint.c).
There are a couple of minor differences between the URBs in the Windows case and the Linux case:
1. The Windows URBs are larger: 448 bytes with a data length of 384 bytes compared to 448 bytes with a data length of 128 bytes for Alsa
I don't know if this is significant or is the impact of Alsa chosing a different format/framerate.
2. The bInterfaceClass in the Windows case is set to Vendor Specific (0xff) but is Unknown (0xffff) in the Alsa case. I can't see where this is being set. The host interfaces seem to have the correct bInterfaceClass
Other than that, the two appear to be the same. The ISO descriptors in the Windows case also appear to be empty:
0000 ee ff ff ff 00 00 00 00 38 00 00 00 00 00 00 00 ........8....... 0010 ee ff ff ff 38 00 00 00 38 00 00 00 00 00 00 00 ....8...8....... 0020 ee ff ff ff 70 00 00 00 38 00 00 00 00 00 00 00 ....p...8....... 0030 ee ff ff ff a8 00 00 00 38 00 00 00 00 00 00 00 ........8....... 0040 ee ff ff ff e0 00 00 00 38 00 00 00 00 00 00 00 ........8....... 0050 ee ff ff ff 18 01 00 00 38 00 00 00 00 00 00 00 ........8....... 0060 ee ff ff ff 50 01 00 00 38 00 00 00 00 00 00 00 ....P...8....... 0070 ee ff ff ff 88 01 00 00 38 00 00 00 00 00 00 00 ........8....... 0080 ee ff ff ff c0 01 00 00 38 00 00 00 00 00 00 00 ........8....... 0090 ee ff ff ff f8 01 00 00 38 00 00 00 00 00 00 00 ........8....... 00a0 ee ff ff ff 30 02 00 00 38 00 00 00 00 00 00 00 ....0...8....... 00b0 ee ff ff ff 68 02 00 00 38 00 00 00 00 00 00 00 ....h...8....... 00c0 ee ff ff ff a0 02 00 00 38 00 00 00 00 00 00 00 ........8....... 00d0 ee ff ff ff d8 02 00 00 38 00 00 00 00 00 00 00 ........8....... 00e0 ee ff ff ff 10 03 00 00 38 00 00 00 00 00 00 00 ........8....... 00f0 ee ff ff ff 48 03 00 00 38 00 00 00 00 00 00 00 ....H...8....... 0100 ee ff ff ff 80 03 00 00 38 00 00 00 00 00 00 00 ........8....... 0110 ee ff ff ff b8 03 00 00 38 00 00 00 00 00 00 00 ........8....... 0120 ee ff ff ff f0 03 00 00 38 00 00 00 00 00 00 00 ........8....... 0130 ee ff ff ff 28 04 00 00 38 00 00 00 00 00 00 00 ....(...8....... 0140 ee ff ff ff 60 04 00 00 38 00 00 00 00 00 00 00 ....`...8....... 0150 ee ff ff ff 98 04 00 00 38 00 00 00 00 00 00 00 ........8....... 0160 ee ff ff ff d0 04 00 00 38 00 00 00 00 00 00 00 ........8....... 0170 ee ff ff ff 08 05 00 00 38 00 00 00 00 00 00 00 ........8.......
Cheers,
Keith