USB isoc xfers

Tue Apr 18 21:30:55 UTC 2006

On Tue, 18 Apr 2006, Maksim Yevmenkin wrote:

> this is a work in progress code that i used to receive sco data from the
> headset. this is NOT complete, its for the reference purposes. i have not
> tried to send sco data.

Ahh, thanks - I see that you are using multiple transfers.. I wonder if
that will help with the problems I was seeing today. As you can see in the
attached dump I inserted a line break in between observed packets (handle
0x002d, length 0x30, framesize 9 bytes) but it is clearly nonsense and
there is no way for my code to find where packets start and finish. I
memset the buffer with 0xaa before the transfer and data is missing in
places and present in other places but the frame is marked empty.

In fact most of the problems I see are at the start/end of transfers
though, so that may be the exact fix.

> > So far I am supposing that for USB isoc transfers, the transfer would be
> > fulfilled in any case after a timeout (3ms ?) which is why I get zero
> > bytes, and I would be happy with that but it seems that the uhci/usbdi
> > part gets lost in a loop when I restart the xfer (possibly caused by some
> > DIAGNOSTIC logic)

I found this locking up problem in the uhci code and actually I'm not sure
that you will have come across it (I think the usb code is common) since
your callback routine does not recycle the transfer right away but rather
switches context (?) with the ng_send_fn() call before restarting. I was
doing as (the NetBSD) ugen does and just recycle the xfer directly from
the callback, but something further down was trying to reference the
previous state.

This also might be causing my problems at the start/end of xfers.

> > To have isoc xfers consuming processor cycles continuously when no data is
> > being sent does not seem like a great idea though, maybe I got the wrong
> > impression there..
>
> i do not think we do have a choice here. since the bandwidth is reserved,
> there has to be a transfer pending, otherwise time constrains are not met.

In order to offset this (and also as I was trying to work out what was
going on), I made a sysctl variable to control which alternate
configuration is used - it can only be set before the controller is
enabled and will default to the zero setting so that cycles are not wasted
if the user does not want to use isoc data.

I might take that out though, since it does not seem to impact the system
especially to have transfers completing empty. I roughly noted 2000 in 10
minutes which I think is every ~30ms and hm, thinking about it that would
be about right because each frame is, I think, 1ms, and I was using the
lowest configuration. At 9 bytes per frame, there were 28 frames in the
buffer which I made big enough to handle a maximum SCO packet (0xff + 3).

Ahh, and now I have the idea that it may be better to calculate the isoc
buffer size so that a fixed number of frames fit into each buffer, rather
than calculating the number of frames that will fit into a fixed buffer..
that way, the number of transfers would remain constant over differing
loads as each would be time stable.

regards,
iain
-------------- next part --------------
Apr 18 18:20:23 galant bthcid[399]: Sending Link_Key_Reply to ubt0 for remote bdaddr 00:07:a4:23:10:83
Apr 18 18:20:24 galant /netbsd: ubt_recv_sco_complete: sc=0xc0a07a00, count=33
Apr 18 18:20:24 galant /netbsd: frame  0 (size  0): a4 01 39 01 bc 00 c9 00 6e
Apr 18 18:20:24 galant /netbsd: frame  1 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  2 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  3 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  4 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  5 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  6 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  7 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  8 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  9 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 10 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 11 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 12 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 13 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 14 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 15 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 16 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 17 (size  0): ff ff ec ff 19 ff 61 fc e6
Apr 18 18:20:24 galant /netbsd: frame 18 (size  0): f7 a3 f4 bf f2 11 ed cf ec
Apr 18 18:20:24 galant /netbsd: frame 19 (size  0): 93 ed 83 eb 06 f4 aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 20 (size  0): 2d 00 30 bc ee 7b f2 1a fd
Apr 18 18:20:24 galant /netbsd: frame 21 (size  0): c1 f6 f9 fa 0b fe dd f7 84
Apr 18 18:20:24 galant /netbsd: frame 22 (size  0): 00 c9 fa 96 fe 7f ff ca fb
Apr 18 18:20:24 galant /netbsd: frame 23 (size  0): b2 00 62 fd d0 ff 7b ff bc
Apr 18 18:20:24 galant /netbsd: frame 24 (size  0): fe 98 00 76 01 c2 00 fa 00
Apr 18 18:20:24 galant /netbsd: frame 25 (size  6): 68 00 91 00 53 00 aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 26 (size  9): 2d 00 30 4f 00 4e 01 d8 01
Apr 18 18:20:24 galant /netbsd: frame 27 (size  9): 42 01 d8 00 d1 00 1e 01 d6
Apr 18 18:20:24 galant /netbsd: frame 28 (size  9): 00 b8 00 7c 00 6f 00 dd 00
Apr 18 18:20:24 galant /netbsd: ptr=0xc08c095a, buf=0xcaa8e105, m_len=34, count=33, m_pkthdr.len=34
Apr 18 18:20:24 galant /netbsd: ubt_recv_sco_complete: sc=0xc0a07a00, count=135
Apr 18 18:20:24 galant /netbsd: frame  0 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  1 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  2 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  3 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  4 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  5 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  6 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  7 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  8 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  9 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 10 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 11 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 12 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame 13 (size  9): 00 75 00 71 00 17 01 8e 01
Apr 18 18:20:24 galant /netbsd: frame 14 (size  6): 12 00 88 00 23 01 aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 15 (size  9): 2d 00 30 fb 00 8c 00 90 00
Apr 18 18:20:24 galant /netbsd: frame 16 (size  9): 5c 00 4d 00 41 00 44 00 fb
Apr 18 18:20:24 galant /netbsd: frame 17 (size  9): ff 4d ff 86 ff a7 ff 46 ff
Apr 18 18:20:24 galant /netbsd: frame 18 (size  9): 4e 00 4a 00 28 00 02 00 00
Apr 18 18:20:24 galant /netbsd: frame 19 (size  9): 00 ff ff 00 00 fd ff 00 00
Apr 18 18:20:24 galant /netbsd: frame 20 (size  6): fe ff ff ff ff ff aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 21 (size  9): 2d 00 30 fe ff ff ff fe ff
Apr 18 18:20:24 galant /netbsd: frame 22 (size  9): ff ff fe ff fe ff fe ff fe
Apr 18 18:20:24 galant /netbsd: frame 23 (size  9): ff ff ff fe ff fe ff ff ff
Apr 18 18:20:24 galant /netbsd: frame 24 (size  9): fe ff fe ff ff ff fe ff ff
Apr 18 18:20:24 galant /netbsd: frame 25 (size  9): ff fe ff d8 ff ce ff c4 ff
Apr 18 18:20:24 galant /netbsd: frame 26 (size  6): 65 ff 6d ff b5 ff aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 27 (size  9): 2d 00 30 a8 ff c0 ff 75 ff
Apr 18 18:20:24 galant /netbsd: frame 28 (size  9): 50 ff a0 ff a2 ff bf ff 99
Apr 18 18:20:24 galant /netbsd: ptr=0xc08c09c0, buf=0xcaa8e105, m_len=136, count=135, m_pkthdr.len=136
Apr 18 18:20:24 galant /netbsd: ubt_recv_sco_complete: sc=0xc0a07a00, count=237
Apr 18 18:20:24 galant /netbsd: frame  0 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  1 (size  9): 57 ff 9c ff 76 ff 54 ff 6f
Apr 18 18:20:24 galant /netbsd: frame  2 (size  9): ff 94 ff 5b ff 57 ff 85 ff
Apr 18 18:20:24 galant /netbsd: frame  3 (size  6): 49 ff 56 ff 5d ff aa aa aa

Apr 18 18:20:24 galant /netbsd: frame  4 (size  9): 2d 00 30 27 ff 3d ff 39 ff
Apr 18 18:20:24 galant /netbsd: frame  5 (size  9): 2c ff 34 ff 1c ff 33 ff 54
Apr 18 18:20:24 galant /netbsd: frame  6 (size  9): ff 3e ff 21 ff 25 ff 23 ff
Apr 18 18:20:24 galant /netbsd: frame  7 (size  9): 1e ff 17 ff 0a ff 05 ff 11
Apr 18 18:20:24 galant /netbsd: frame  8 (size  9): ff f7 fe 05 ff 1b ff 0d ff
Apr 18 18:20:24 galant /netbsd: frame  9 (size  6): eb fe 03 ff 0e ff aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 10 (size  9): 2d 00 30 ef fe 0b ff 02 ff
Apr 18 18:20:24 galant /netbsd: frame 11 (size  9): e1 fe f8 fe f0 fe f9 fe ed
Apr 18 18:20:24 galant /netbsd: frame 12 (size  9): fe eb fe 10 ff f2 fe c6 fe
Apr 18 18:20:24 galant /netbsd: frame 13 (size  9): ea fe ec fe dd fe ee fe da
Apr 18 18:20:24 galant /netbsd: frame 14 (size  9): fe d7 fe eb fe fa fe e5 fe
Apr 18 18:20:24 galant /netbsd: frame 15 (size  6): d9 fe e9 fe f7 fe aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 16 (size  9): 2d 00 30 c9 fe c4 fe ed fe
Apr 18 18:20:24 galant /netbsd: frame 17 (size  9): be fe a2 fe a7 fe b1 fe b8
Apr 18 18:20:24 galant /netbsd: frame 18 (size  9): fe cd fe d4 fe cd fe c6 fe
Apr 18 18:20:24 galant /netbsd: frame 19 (size  9): d1 fe c3 fe cb fe b4 fe c3
Apr 18 18:20:24 galant /netbsd: frame 20 (size  9): fe cf fe c4 fe de fe c6 fe
Apr 18 18:20:24 galant /netbsd: frame 21 (size  6): a6 fe bf fe b1 fe aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 22 (size  9): 2d 00 30 af fe d3 fe c9 fe
Apr 18 18:20:24 galant /netbsd: frame 23 (size  9): b5 fe bd fe ca fe be fe cd
Apr 18 18:20:24 galant /netbsd: frame 24 (size  9): fe b7 fe b4 fe cb fe ac fe
Apr 18 18:20:24 galant /netbsd: frame 25 (size  9): b1 fe ae fe 92 fe c0 fe cb
Apr 18 18:20:24 galant /netbsd: frame 26 (size  9): fe ae fe c5 fe bf fe af fe
Apr 18 18:20:24 galant /netbsd: frame 27 (size  6): bf fe ac fe ac fe aa aa aa

Apr 18 18:20:24 galant /netbsd: frame 28 (size  9): 2d 00 30 aa fe 96 fe c0 fe
Apr 18 18:20:24 galant /netbsd: ptr=0xc08c0c4a, buf=0xcaa8e105, m_len=42, count=237, m_pkthdr.len=238
Apr 18 18:20:24 galant /netbsd: ubt_recv_sco_complete: sc=0xc0a07a00, count=237
Apr 18 18:20:24 galant /netbsd: frame  0 (size  0): aa aa aa aa aa aa aa aa aa
Apr 18 18:20:24 galant /netbsd: frame  1 (size  9): fe b7 fe be fe 9b fe b8 fe
Apr 18 18:20:24 galant /netbsd: frame  2 (size  9): 97 fe b9 fe b2 fe a9 fe aa
Apr 18 18:20:24 galant /netbsd: frame  3 (size  9): fe 8c fe bd fe c0 fe a7 fe
Apr 18 18:20:24 galant /netbsd: frame  4 (size  6): af fe ac fe af fe aa aa aa