Comment 70 for bug 1315212

for unknown reason which pulseaudio did not probe surround40

pulseaudio still using timer base scheduling in your last log

but it was strange tradtional mode was used in your first log

20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.name = "CA0106"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.id = "ca0106"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.subdevice = "0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.subdevice_name = "subdevice #0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.device = "0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.card = "0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.card_name = "CA0106"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.long_card_name = "Live! 7.1 24bit [SB0410] at 0xcf00 irq 19"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: alsa.driver_name = "snd_ca0106"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.bus_path = "pci-0000:06:00.0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: sysfs.path = "/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/0000:06:00.0/sound/card0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.bus = "pci"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.vendor.id = "1102"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.vendor.name = "Creative Labs"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.product.id = "0007"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.product.name = "CA0106 Soundblaster (SB0410 SBLive! 24-bit)"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.string = "front:0"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.buffering.buffer_size = "65536"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.buffering.fragment_size = "32768"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.access_mode = "mmap+timer"
Jan 02 20:25:49 homecomp pulseaudio[11971]: [pulseaudio] sink.c: device.profile.name = "analog-stereo"

Dec 25 19:33:27 homecomp pulseaudio[1911]: module-stream-restore.id = "sink-input-by-application-name:paplay"
Dec 25 19:33:27 homecomp pulseaudio[1911]: Requested tlength=2000.00 ms, minreq=20.00 ms
Dec 25 19:33:27 homecomp pulseaudio[1911]: Traditional mode enabled, modifying sink usec only for compat with minreq.
Dec 25 19:33:27 homecomp pulseaudio[1911]: Requested latency=1960.00 ms, Received latency=341.33 ms
Dec 25 19:33:27 homecomp pulseaudio[1911]: memblockq requested: maxlength=4194304, tlength=192000, base=2, prebuf=190082, minreq=1920 maxrewind=0
Dec 25 19:33:27 homecomp pulseaudio[1911]: memblockq sanitized: maxlength=4194304, tlength=192000, base=2, prebuf=190082, minreq=1920 maxrewind=0
Dec 25 19:33:27 homecomp pulseaudio[1911]: Final latency 2341.33 ms = 1960.00 ms + 2*20.00 ms + 341.33 ms
Dec 25 19:33:27 homecomp pulseaudio[1911]: Latency set to 26.00ms
Dec 25 19:33:27 homecomp pulseaudio[1911]: hwbuf_unused=60544
Dec 25 19:33:27 homecomp pulseaudio[1911]: setting avail_min=15617

the driver need to provide accurate hw_ptr position in order to set hwbuf_unused to non zero

the actual buffer used = buffer size (65536) - hwbuf_unused (60544) is 5012 bytes