这是我的 dmesg
[ 0.000000] Linux version 3.2.0 (winking@winking-ubuntu) (gcc version 4.7.3 20130226 (prerelease) (crosstool-NG linaro-1.13.1-4.7-2013.03-20130313 - Linaro GCC 2013.03) ) #3 Sat Jul 26 10:34:00 CST 2014
[ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] Machine: am335xevm
[ 0.000000] Memory policy: ECC disabled, Data cache writeback
[ 0.000000] On node 0 totalpages: 131072
[ 0.000000] free_area_init_node: node 0, pgdat c063c310, node_mem_map c0675000
[ 0.000000] Normal zone: 1024 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 130048 pages, LIFO batch:31
[ 0.000000] AM335X ES2.0 (sgx neon )
[ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
[ 0.000000] pcpu-alloc: [0] 0
[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 130048
[ 0.000000] Kernel command line: console=ttyO1,115200n8 mem=512M root=/dev/nfs nfsroot=192.168.1.108:/Sitara/targetNFS4,nolock rw ip=dhcp
[ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
[ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
[ 0.000000] Memory: 512MB = 512MB total
[ 0.000000] Memory: 513140k/513140k available, 11148k reserved, 0K highmem
[ 0.000000] Virtual kernel memory layout:
[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[ 0.000000] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
[ 0.000000] vmalloc : 0xe0800000 - 0xff000000 ( 488 MB)
[ 0.000000] lowmem : 0xc0000000 - 0xe0000000 ( 512 MB)
[ 0.000000] modules : 0xbf000000 - 0xc0000000 ( 16 MB)
[ 0.000000] .text : 0xc0008000 - 0xc05a0000 (5728 kB)
[ 0.000000] .init : 0xc05a0000 - 0xc05db000 ( 236 kB)
[ 0.000000] .data : 0xc05dc000 - 0xc0645b20 ( 423 kB)
[ 0.000000] .bss : 0xc0645b44 - 0xc0674824 ( 188 kB)
[ 0.000000] NR_IRQS:396
[ 0.000000] IRQ: Found an INTC at 0xfa200000 (revision 5.0) with 128 interrupts
[ 0.000000] Total of 128 interrupts on 1 active controller
[ 0.000000] OMAP clockevent source: GPTIMER2 at 24000000 Hz
[ 0.000000] omap_dm_timer_switch_src: Switching to HW default clocksource(sys_clkin_ck) for timer1, this may impact timekeeping in low power state
[ 0.000000] OMAP clocksource: GPTIMER1 at 24000000 Hz
[ 0.000000] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 178956ms
[ 0.000000] Console: colour dummy device 80x30
[ 0.000157] Calibrating delay loop... 996.14 BogoMIPS (lpj=4980736)
[ 0.087767] pid_max: default: 32768 minimum: 301
[ 0.087858] Security Framework initialized
[ 0.087936] Mount-cache hash table entries: 512
[ 0.088243] CPU: Testing write buffer coherency: ok
[ 0.088849] devtmpfs: initialized
[ 0.107793] omap_hwmod: pruss: failed to hardreset
[ 0.108689] print_constraints: dummy:
[ 0.108967] NET: Registered protocol family 16
[ 0.110594] OMAP GPIO hardware version 0.1
[ 0.112551] omap_mux_init: Add partition: #1: core, flags: 0
[ 0.114022] omap_i2c.1: alias fck already exists
[ 0.114715] omap2_mcspi.1: alias fck already exists
[ 0.114885] omap2_mcspi.2: alias fck already exists
[ 0.115572] edma.0: alias fck already exists
[ 0.115588] edma.0: alias fck already exists
[ 0.115602] edma.0: alias fck already exists
[ 0.136035] bio: create slab <bio-0> at 0
[ 0.137941] SCSI subsystem initialized
[ 0.139180] usbcore: registered new interface driver usbfs
[ 0.139418] usbcore: registered new interface driver hub
[ 0.139579] usbcore: registered new device driver usb
[ 0.139818] registerd cppi-dma Intr @ IRQ 17
[ 0.139828] Cppi41 Init Done Qmgr-base(e087a000) dma-base(e0878000)
[ 0.139835] Cppi41 Init Done
[ 0.139859] musb-ti81xx musb-ti81xx: musb0, board_mode=0x13, plat_mode=0x3
[ 0.140086] musb-ti81xx musb-ti81xx: musb1, board_mode=0x13, plat_mode=0x1
[ 0.140947] omap_i2c omap_i2c.1: bus 1 rev2.4.0 at 100 kHz
[ 0.142043] tps65910 1-002d: could not be detected
[ 0.143034] Advanced Linux Sound Architecture Driver Version 1.0.24.
[ 0.143953] Switching to clocksource gp timer
[ 0.157321] musb-hdrc: version 6.0, ?dma?, otg (peripheral+host)
[ 0.157472] musb-hdrc musb-hdrc.0: dma type: dma-cppi41
[ 0.157733] MUSB0 controller's USBSS revision = 4ea20800
[ 0.157749] TxFifo Empty intr disabled
[ 0.157757] musb0: Enabled SW babble control
[ 0.157987] musb-hdrc: ConfigData=0xde (UTMI-8, dyn FIFOs, bulk combine, bulk split, HB-ISO Rx, HB-ISO Tx, SoftConn)
[ 0.158001] musb-hdrc: MHDRC RTL version 2.0
[ 0.158009] musb-hdrc: setup fifo_mode 4
[ 0.158032] musb-hdrc: 28/31 max ep, 16384/16384 memory
[ 0.158044] musb-hdrc.0: bulk split disabled
[ 0.158050] musb-hdrc.0: bulk combine disabled
[ 0.158490] musb-hdrc musb-hdrc.0: USB OTG mode controller at e083c000 using DMA, IRQ 18
[ 0.158630] musb-hdrc musb-hdrc.1: dma type: dma-cppi41
[ 0.158872] MUSB1 controller's USBSS revision = 4ea20800
[ 0.158885] TxFifo Empty intr disabled
[ 0.158893] musb1: Enabled SW babble control
[ 0.159111] musb-hdrc: ConfigData=0xde (UTMI-8, dyn FIFOs, bulk combine, bulk split, HB-ISO Rx, HB-ISO Tx, SoftConn)
[ 0.159124] musb-hdrc: MHDRC RTL version 2.0
[ 0.159130] musb-hdrc: setup fifo_mode 4
[ 0.159150] musb-hdrc: 28/31 max ep, 16384/16384 memory
[ 0.159159] musb-hdrc.1: bulk split disabled
[ 0.159165] musb-hdrc.1: bulk combine disabled
[ 0.159221] musb-hdrc musb-hdrc.1: MUSB HDRC host driver
[ 0.159295] musb-hdrc musb-hdrc.1: new USB bus registered, assigned bus number 1
[ 0.159398] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[ 0.159409] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 0.159420] usb usb1: Product: MUSB HDRC host driver
[ 0.159427] usb usb1: Manufacturer: Linux 3.2.0 musb-hcd
[ 0.159435] usb usb1: SerialNumber: musb-hdrc.1
[ 0.160170] hub 1-0:1.0: USB hub found
[ 0.160194] hub 1-0:1.0: 1 port detected
[ 0.160656] musb-hdrc musb-hdrc.1: USB Host mode controller at e083e800 using DMA, IRQ 19
[ 0.160997] NET: Registered protocol family 2
[ 0.161148] IP route cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.161395] TCP established hash table entries: 16384 (order: 5, 131072 bytes)
[ 0.161609] TCP bind hash table entries: 16384 (order: 4, 65536 bytes)
[ 0.161735] TCP: Hash tables configured (established 16384 bind 16384)
[ 0.161744] TCP reno registered
[ 0.161753] UDP hash table entries: 256 (order: 0, 4096 bytes)
[ 0.161770] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[ 0.161925] NET: Registered protocol family 1
[ 0.162132] RPC: Registered named UNIX socket transport module.
[ 0.162141] RPC: Registered udp transport module.
[ 0.162147] RPC: Registered tcp transport module.
[ 0.162154] RPC: Registered tcp NFSv4.1 backchannel transport module.
[ 0.162325] NetWinder Floating Point Emulator V0.97 (double precision)
[ 0.179277] VFS: Disk quotas dquot_6.5.2
[ 0.179333] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[ 0.179754] msgmni has been set to 1002
[ 0.182177] alg: No test for stdrng (krng)
[ 0.182773] io scheduler noop registered
[ 0.182784] io scheduler deadline registered
[ 0.182837] io scheduler cfq registered (default)
[ 0.183750] Could not set LED4 to fully on
[ 0.224873] omap_uart.0: ttyO0 at MMIO 0x44e09000 (irq = 72) is a OMAP UART0
[ 0.225289] omap_uart.1: ttyO1 at MMIO 0x48022000 (irq = 73) is a OMAP UART1
[ 0.833105] console [ttyO1] enabled
[ 0.837229] omap_uart.2: ttyO2 at MMIO 0x48024000 (irq = 74) is a OMAP UART2
[ 0.845004] omap_uart.3: ttyO3 at MMIO 0x481a6000 (irq = 44) is a OMAP UART3
[ 0.852723] omap_uart.4: ttyO4 at MMIO 0x481a8000 (irq = 45) is a OMAP UART4
[ 0.860470] omap_uart.5: ttyO5 at MMIO 0x481aa000 (irq = 46) is a OMAP UART5
[ 0.868603] omap4_rng omap4_rng: OMAP4 Random Number Generator ver. 2.00
[ 0.882886] brd: module loaded
[ 0.890161] loop: module loaded
[ 0.893581] i2c-core: driver [tsl2550] using legacy suspend method
[ 0.900081] i2c-core: driver [tsl2550] using legacy resume method
[ 0.906510] at24 1-0051: 32768 byte 24c256 EEPROM, writable, 64 bytes/write
[ 0.973986] No daughter card found
[ 0.977569] at24 1-0050: 32768 byte 24c256 EEPROM, writable, 64 bytes/write
[ 0.984854] The board is a Chipsee Beaglebone Black Expansion.
[ 0.991233] omap_hsmmc.0: alias fck already exists
[ 0.997015] da8xx_lcdc.0: alias fck already exists
[ 1.002434] da8xx_lcdc da8xx_lcdc.0: GLCD: Found HJ070NA13A panel
[ 1.027228] Console: switching to colour frame buffer device 128x37
[ 1.043171] omap_i2c.2: alias fck already exists
[ 1.048590] omap_i2c omap_i2c.2: bus 2 rev2.4.0 at 100 kHz
[ 1.054497] usb 1-1: new high-speed USB device number 2 using musb-hdrc
[ 1.062564] davinci-mcasp.0: alias fck already exists
[ 1.068822] d_can.0: alias fck already exists
[ 1.076131] mtdoops: mtd device (mtddev=name/number) must be supplied
[ 1.083177] omap2-nand driver initializing
[ 1.087635] OneNAND driver initializing
[ 1.092684] CAN device driver interface
[ 1.096719] CAN bus driver for Bosch D_CAN controller 1.0
[ 1.103006] d_can d_can.0: device registered (irq=52, irq_obj=53)
[ 1.153996] davinci_mdio davinci_mdio.0: davinci mdio revision 1.6
[ 1.160462] davinci_mdio davinci_mdio.0: detected phy mask fffffffe
[ 1.167621] davinci_mdio.0: probed
[ 1.171179] davinci_mdio davinci_mdio.0: phy[0]: device 0:00, driver SMSC LAN8710/LAN8720
[ 1.180119] usbcore: registered new interface driver zd1201
[ 1.186119] usbcore: registered new interface driver cdc_ether
[ 1.192329] usbcore: registered new interface driver cdc_eem
[ 1.198531] usbcore: registered new interface driver dm9601
[ 1.204423] cdc_ncm: 04-Aug-2011
[ 1.208053] usbcore: registered new interface driver cdc_ncm
[ 1.213968] Initializing USB Mass Storage driver...
[ 1.219387] usbcore: registered new interface driver usb-storage
[ 1.225687] USB Mass Storage support registered.
[ 1.230791] usb 1-1: New USB device found, idVendor=20b1, idProduct=3022
[ 1.237817] usb 1-1: New USB device strings: Mfr=1, Product=3, SerialNumber=0
[ 1.245285] usb 1-1: Product: Pureaudio xDAC
[ 1.249744] usb 1-1: Manufacturer: Pureaudio
[ 1.254539] mousedev: PS/2 mouse device common for all mice
[ 1.262402] input: ft5x06_ts as /devices/virtual/input/input0
[ 1.270233] input: ti-tsc as /devices/platform/omap/ti_tscadc/tsc/input/input1
[ 1.278571] i2c /dev entries driver
[ 1.282727] Linux video capture interface: v2.00
[ 1.287848] usbcore: registered new interface driver uvcvideo
[ 1.293854] USB Video Class driver (1.1.1)
[ 1.554823] OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec
[ 1.561311] _regulator_get: deviceless supply vdd_mpu not found, using dummy regulator
[ 1.569942] cpuidle: using governor ladder
[ 1.574613] cpuidle: using governor menu
[ 1.580789] Registered led device: am335x:Chipsee:mmc0
[ 1.580966] Registered led device: am335x:Chipsee:heartbeat
[ 1.581084] omap4_aes_mod_init: loading AM33X AES driver
[ 1.586755] omap4-aes omap4-aes: AM33X AES hw accel rev: 3.02
[ 1.593196] omap4_aes_probe: probe() done
[ 1.597820] omap4_sham_mod_init: loading AM33X SHA/MD5 driver
[ 1.603930] omap4-sham omap4-sham: AM33X SHA/MD5 hw accel rev: 4.03
[ 1.614505] omap4_sham_probe: probe() done
[ 1.623928] usbcore: registered new interface driver usbhid
[ 1.629781] usbhid: USB HID core driver
[ 1.634430] tiadc tiadc: attached adc driver
[ 1.664872] mmc0: host does not support reading read-only switch. assuming write-enable.
[ 1.675392] mmc0: new high speed SDHC card at address 1234
[ 1.681621] mmcblk0: mmc0:1234 SA08G 7.28 GiB
[ 1.688308] mmcblk0: p1 p2
[ 1.721055] ALSA sound/usb/mixer.c:342 cannot get ctl value: req = 0x83, wValue = 0x201, wIndex = 0xa00, type = 4
[ 1.731878] ALSA sound/usb/mixer.c:342 cannot get ctl value: req = 0x83, wValue = 0x200, wIndex = 0xa00, type = 4
[ 1.743638] usbcore: registered new interface driver snd-usb-audio
[ 1.750309] usbcore: registered new interface driver snd-usb-caiaq
[ 1.758351] _regulator_get: 2-001b supply IOVDD not found, using dummy regulator
[ 1.766165] _regulator_get: 2-001b supply DVDD not found, using dummy regulator
[ 1.773840] _regulator_get: 2-001b supply AVDD not found, using dummy regulator
[ 1.781536] _regulator_get: 2-001b supply DRVDD not found, using dummy regulator
[ 1.791386] asoc: tlv320aic3x-hifi <-> davinci-mcasp.0 mapping ok
[ 1.799021] ALSA device list:
[ 1.802126] #0: Pureaudio Pureaudio xDAC at usb-musb-hdrc.1-1, high speed
[ 1.809432] #1: AM335X EVM
[ 1.812442] oprofile: hardware counters not available
[ 1.817734] oprofile: using timer interrupt.
[ 1.822216] nf_conntrack version 0.5.0 (8017 buckets, 32068 max)
[ 1.828964] ip_tables: (C) 2000-2006 Netfilter Core Team
[ 1.834637] TCP cubic registered
[ 1.838011] NET: Registered protocol family 17
[ 1.842659] can: controller area network core (rev 20090105 abi 8)
[ 1.849203] NET: Registered protocol family 29
[ 1.853862] can: raw protocol (rev 20090105)
[ 1.858336] can: broadcast manager protocol (rev 20090105 t)
[ 1.864288] Registering the dns_resolver key type
[ 1.869261] VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 3
[ 1.877288] ThumbEE CPU extension supported.
[ 1.881807] mux: Failed to setup hwmod io irq -22
[ 1.887281] Power Management for AM33XX family
[ 1.892104] Trying to load am335x-pm-firmware.bin (60 secs timeout)
[ 1.898805] Copied the M3 firmware to UMEM
[ 1.903161] Cortex M3 Firmware Version = 0x18
[ 1.908230] sr_init: platform driver register failed
[ 1.916242] clock: disabling unused clocks to save power
[ 1.931577] Detected MACID=d0:39:72:3b:d1:e6
[ 1.936905] cpsw: Detected MACID = d0:39:72:3b:d1:e8
[ 1.942936] drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
[ 1.953641] net eth0: CPSW phy found : id is : 0x7c0f1
[ 1.965931] PHY 0:01 not found
[ 4.944525] PHY: 0:00 - Link is Up - 100/Full
[ 4.963997] Sending DHCP requests .
[ 5.467413] DHCP/BOOTP: Ignoring delayed packet
[ 8.423983] ., OK
[ 8.934450] IP-Config: Got DHCP answer from 0.0.0.0, my address is 192.168.1.115
[ 8.945014] IP-Config: Complete:
[ 8.948397] device=eth0, addr=192.168.1.115, mask=255.255.255.0, gw=192.168.1.1,
[ 8.956346] host=192.168.1.115, domain=domain, nis-domain=(none),
[ 8.963168] bootserver=0.0.0.0, rootserver=192.168.1.108, rootpath=, mtu=576
[ 8.979207] VFS: Mounted root (nfs filesystem) on device 0:15.
[ 8.986071] devtmpfs: mounted
[ 8.989487] Freeing init memory: 236K
>[ 9.691499] udevd[886]: starting version 182
==================================================================
usb DMA 是后来开启的，开不开启，听起来都没什么影响。
听音乐感觉有些爆音的感觉，
这个 USB 声卡用同一套软件在PC 机上播放是没有问题的。
个挺郁闷的.
