In contrast the Micro USB log (when midi works) looked like this:
root@bela:~# dmesg -w
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Initializing cgroup subsys cpuacct
[ 0.000000] Linux version 4.4.113-ti-xenomai-r149 (root@giulio-VirtualBox) (gcc version 5.5.0 (Linaro GCC 5.5-2017.10) ) #1 PREEMPT Wed Sep 26 15:40:33 BST 2018
[ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] Machine model: TI AM335x PocketBeagle
[ 0.000000] Memory policy: Data cache writeback
[ 0.000000] On node 0 totalpages: 131072
[ 0.000000] free_area_init_node: node 0, pgdat c100bb04, node_mem_map dfb79000
[ 0.000000] Normal zone: 1152 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 131072 pages, LIFO batch:31
[ 0.000000] CPU: All CPU(s) started in SVC mode.
[ 0.000000] AM335X ES2.1 (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: 129920
[ 0.000000] Kernel command line: console=ttyS0,115200n8 root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet
[ 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: 500720K/524288K available (11518K kernel code, 872K rwdata, 3656K rodata, 456K init, 967K bss, 23568K reserved, 0K cma-reserved, 0K highmem)
[ 0.000000] Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
vmalloc : 0xe0800000 - 0xff800000 ( 496 MB)
lowmem : 0xc0000000 - 0xe0000000 ( 512 MB)
pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
.text : 0xc0008000 - 0xc0ed9b68 (15175 kB)
.init : 0xc0eda000 - 0xc0f4c000 ( 456 kB)
.data : 0xc0f4c000 - 0xc10260bc ( 873 kB)
.bss : 0xc1029000 - 0xc111ae04 ( 968 kB)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] Preemptible hierarchical RCU implementation.
[ 0.000000] Build-time adjustment of leaf fanout to 32.
[ 0.000000] NR_IRQS:16 nr_irqs:16 16
[ 0.000000] IRQ: Found an INTC at 0xfa200000 (revision 5.0) with 128 interrupts
[ 0.000000] OMAP clockevent source: timer2 at 24000000 Hz
[ 0.000020] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
[ 0.000049] I-pipe, 24.000 MHz clocksource, wrap in 178956 ms
[ 0.000072] clocksource: ipipe_tsc: mask: 0xffffffffffffffff max_cycles: 0x588fe9dc0, max_idle_ns: 440795202592 ns
[ 0.000098] clocksource: timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
[ 0.000108] OMAP clocksource: timer1 at 24000000 Hz
[ 0.002146] clocksource_probe: no matching clocksources found
[ 0.002709] Interrupt pipeline (release #9)
[ 0.003027] Console: colour dummy device 80x30
[ 0.003079] Calibrating delay loop... 995.32 BogoMIPS (lpj=1990656)
[ 0.020717] pid_max: default: 32768 minimum: 301
[ 0.020872] Security Framework initialized
[ 0.020889] Yama: becoming mindful.
[ 0.020932] AppArmor: AppArmor disabled by boot time parameter
[ 0.020983] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.020997] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.021885] Initializing cgroup subsys io
[ 0.021919] Initializing cgroup subsys memory
[ 0.021971] Initializing cgroup subsys devices
[ 0.021991] Initializing cgroup subsys freezer
[ 0.022010] Initializing cgroup subsys net_cls
[ 0.022027] Initializing cgroup subsys perf_event
[ 0.022046] Initializing cgroup subsys net_prio
[ 0.022070] Initializing cgroup subsys pids
[ 0.022132] CPU: Testing write buffer coherency: ok
[ 0.022654] Setting up static identity map for 0x80008200 - 0x80008260
[ 0.028133] devtmpfs: initialized
[ 0.081848] VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 3
[ 0.171738] omap_hwmod: debugss: _wait_target_disable failed
[ 0.226305] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[ 0.226341] futex hash table entries: 256 (order: -1, 3072 bytes)
[ 0.226986] xor: measuring software checksum speed
[ 0.264734] arm4regs : 1146.000 MB/sec
[ 0.304688] 8regs : 909.000 MB/sec
[ 0.344684] 32regs : 1028.000 MB/sec
[ 0.384687] neon : 1377.000 MB/sec
[ 0.384698] xor: using function: neon (1377.000 MB/sec)
[ 0.384743] pinctrl core: initialized pinctrl subsystem
[ 0.387649] NET: Registered protocol family 16
[ 0.389446] DMA: preallocated 1024 KiB pool for atomic coherent allocations
[ 0.399606] OMAP GPIO hardware version 0.1
[ 0.426291] No ATAGs?
[ 0.426334] hw-breakpoint: debug architecture 0x4 unsupported.
[ 0.520749] raid6: neonx2 gen() 1849 MB/s
[ 0.588692] raid6: neonx2 xor() 1137 MB/s
[ 0.588704] raid6: using algorithm neonx2 gen() 1849 MB/s
[ 0.588714] raid6: .... xor() 1137 MB/s, rmw enabled
[ 0.588723] raid6: using intx1 recovery algorithm
[ 0.601765] edma 49000000.edma: TI EDMA DMA engine driver
[ 0.613005] SCSI subsystem initialized
[ 0.613455] libata version 3.00 loaded.
[ 0.613895] usbcore: registered new interface driver usbfs
[ 0.613988] usbcore: registered new interface driver hub
[ 0.614111] usbcore: registered new device driver usb
[ 0.615154] omap_i2c 44e0b000.i2c: could not find pctldev for node /ocp/l4_wkup@44c00000/scm@210000/pinmux@800/pinmux_i2c0_pins, deferring probe
[ 0.615229] omap_i2c 4802a000.i2c: could not find pctldev for node /ocp/l4_wkup@44c00000/scm@210000/pinmux@800/pinmux_i2c1_pins, deferring probe
[ 0.616158] omap_i2c 4819c000.i2c: bus 2 rev0.11 at 400 kHz
[ 0.616578] media: Linux media interface: v0.10
[ 0.616679] Linux video capture interface: v2.00
[ 0.616888] pps_core: LinuxPPS API ver. 1 registered
[ 0.616899] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[ 0.616936] PTP clock support registered
[ 0.618095] omap-mailbox 480c8000.mailbox: omap mailbox rev 0x400
[ 0.619790] NetLabel: Initializing
[ 0.619811] NetLabel: domain hash size = 128
[ 0.619820] NetLabel: protocols = UNLABELED CIPSOv4
[ 0.619907] NetLabel: unlabeled traffic allowed by default
[ 0.620330] clocksource: Switched to clocksource ipipe_tsc
[ 0.787342] NET: Registered protocol family 2
[ 0.788427] TCP established hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.788483] TCP bind hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.788527] TCP: Hash tables configured (established 4096 bind 4096)
[ 0.788624] UDP hash table entries: 256 (order: 0, 4096 bytes)
[ 0.788646] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[ 0.788895] NET: Registered protocol family 1
[ 0.789579] RPC: Registered named UNIX socket transport module.
[ 0.789597] RPC: Registered udp transport module.
[ 0.789606] RPC: Registered tcp transport module.
[ 0.789615] RPC: Registered tcp NFSv4.1 backchannel transport module.
[ 0.790762] hw perfevents: enabled with armv7_cortex_a8 PMU driver, 5 counters available
[ 0.794654] audit: initializing netlink subsys (disabled)
[ 0.794770] audit: type=2000 audit(0.792:1): initialized
[ 0.795709] [Xenomai] scheduling class idle registered.
[ 0.795724] [Xenomai] scheduling class rt registered.
[ 0.795891] I-pipe: head domain Xenomai registered.
[ 0.805258] [Xenomai] Cobalt v3.0.6 (Stellar Parallax) [DEBUG]
[ 0.817988] zbud: loaded
[ 0.818795] VFS: Disk quotas dquot_6.6.0
[ 0.819118] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[ 0.822691] NFS: Registering the id_resolver key type
[ 0.822778] Key type id_resolver registered
[ 0.822790] Key type id_legacy registered
[ 0.822827] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[ 0.823287] fuse init (API version 7.23)
[ 0.824107] SGI XFS with ACLs, security attributes, realtime, no debug enabled
[ 0.835467] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 247)
[ 0.835770] io scheduler noop registered
[ 0.835794] io scheduler deadline registered
[ 0.835891] io scheduler cfq registered (default)
[ 0.838369] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
[ 0.839713] gpio-of-helper ocp:cape-universal: Allocated GPIO id=0
[ 0.839923] gpio-of-helper ocp:cape-universal: Allocated GPIO id=1
[ 0.840152] gpio-of-helper ocp:cape-universal: Allocated GPIO id=2
[ 0.840583] gpio-of-helper ocp:cape-universal: Allocated GPIO id=3
[ 0.840803] gpio-of-helper ocp:cape-universal: Allocated GPIO id=4
[ 0.840988] gpio-of-helper ocp:cape-universal: Allocated GPIO id=5
[ 0.841178] gpio-of-helper ocp:cape-universal: Allocated GPIO id=6
[ 0.841361] gpio-of-helper ocp:cape-universal: Allocated GPIO id=7
[ 0.841542] gpio-of-helper ocp:cape-universal: Allocated GPIO id=8
[ 0.841786] gpio-of-helper ocp:cape-universal: Allocated GPIO id=9
[ 0.842006] gpio-of-helper ocp:cape-universal: Allocated GPIO id=10
[ 0.842199] gpio-of-helper ocp:cape-universal: Allocated GPIO id=11
[ 0.842391] gpio-of-helper ocp:cape-universal: Allocated GPIO id=12
[ 0.842575] gpio-of-helper ocp:cape-universal: Allocated GPIO id=13
[ 0.842763] gpio-of-helper ocp:cape-universal: Allocated GPIO id=14
[ 0.842949] gpio-of-helper ocp:cape-universal: Allocated GPIO id=15
[ 0.843136] gpio-of-helper ocp:cape-universal: Allocated GPIO id=16
[ 0.843330] gpio-of-helper ocp:cape-universal: Allocated GPIO id=17
[ 0.843517] gpio-of-helper ocp:cape-universal: Allocated GPIO id=18
[ 0.843726] gpio-of-helper ocp:cape-universal: Allocated GPIO id=19
[ 0.843917] gpio-of-helper ocp:cape-universal: Allocated GPIO id=20
[ 0.844102] gpio-of-helper ocp:cape-universal: Allocated GPIO id=21
[ 0.844299] gpio-of-helper ocp:cape-universal: Allocated GPIO id=22
[ 0.845026] gpio-of-helper ocp:cape-universal: Allocated GPIO id=23
[ 0.845230] gpio-of-helper ocp:cape-universal: Allocated GPIO id=24
[ 0.845431] gpio-of-helper ocp:cape-universal: Allocated GPIO id=25
[ 0.845629] gpio-of-helper ocp:cape-universal: Allocated GPIO id=26
[ 0.845825] gpio-of-helper ocp:cape-universal: Allocated GPIO id=27
[ 0.846022] gpio-of-helper ocp:cape-universal: Allocated GPIO id=28
[ 0.846214] gpio-of-helper ocp:cape-universal: Allocated GPIO id=29
[ 0.846410] gpio-of-helper ocp:cape-universal: Allocated GPIO id=30
[ 0.846600] gpio-of-helper ocp:cape-universal: Allocated GPIO id=31
[ 0.846791] gpio-of-helper ocp:cape-universal: Allocated GPIO id=32
[ 0.846990] gpio-of-helper ocp:cape-universal: Allocated GPIO id=33
[ 0.847179] gpio-of-helper ocp:cape-universal: Allocated GPIO id=34
[ 0.847375] gpio-of-helper ocp:cape-universal: Allocated GPIO id=35
[ 0.847573] gpio-of-helper ocp:cape-universal: Allocated GPIO id=36
[ 0.847772] gpio-of-helper ocp:cape-universal: Allocated GPIO id=37
[ 0.847975] gpio-of-helper ocp:cape-universal: Allocated GPIO id=38
[ 0.848167] gpio-of-helper ocp:cape-universal: Allocated GPIO id=39
[ 0.848555] gpio-of-helper ocp:cape-universal: Allocated GPIO id=40
[ 0.848777] gpio-of-helper ocp:cape-universal: Allocated GPIO id=41
[ 0.848973] gpio-of-helper ocp:cape-universal: Allocated GPIO id=42
[ 0.849170] gpio-of-helper ocp:cape-universal: Allocated GPIO id=43
[ 0.849185] gpio-of-helper ocp:cape-universal: ready
[ 0.853784] wkup_m3_ipc 44e11324.wkup_m3_ipc: could not get rproc handle
[ 0.856171] Serial: 8250/16550 driver, 6 ports, IRQ sharing disabled
[ 0.860227] console [ttyS0] disabled
[ 0.860508] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 158, base_baud = 3000000) is a 8250
[ 0.873898] console [ttyS0] enabled
[ 0.875011] 48022000.serial: ttyS1 at MMIO 0x48022000 (irq = 159, base_baud = 3000000) is a 8250
[ 0.876013] 48024000.serial: ttyS2 at MMIO 0x48024000 (irq = 160, base_baud = 3000000) is a 8250
[ 0.877146] 481a8000.serial: ttyS4 at MMIO 0x481a8000 (irq = 161, base_baud = 3000000) is a 8250
[ 0.879616] [drm] Initialized drm 1.1.0 20060810
[ 0.909156] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 0.909221] ehci-platform: EHCI generic platform driver
[ 0.909624] ehci-omap: OMAP-EHCI Host Controller driver
[ 0.910455] usbcore: registered new interface driver usb-storage
[ 0.914110] 47401300.usb-phy supply vcc not found, using dummy regulator
[ 0.917333] musb-hdrc: ConfigData=0xde (UTMI-8, dyn FIFOs, bulk combine, bulk split, HB-ISO Rx, HB-ISO Tx, SoftConn)
[ 0.917361] musb-hdrc: MHDRC RTL version 2.0
[ 0.917372] musb-hdrc: setup fifo_mode 4
[ 0.917401] musb-hdrc: 28/31 max ep, 16384/16384 memory
[ 0.917592] musb-hdrc musb-hdrc.0.auto: MUSB HDRC host driver
[ 0.917637] musb-hdrc musb-hdrc.0.auto: new USB bus registered, assigned bus number 1
[ 0.918011] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[ 0.918030] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 0.918043] usb usb1: Product: MUSB HDRC host driver
[ 0.918054] usb usb1: Manufacturer: Linux 4.4.113-ti-xenomai-r149 musb-hcd
[ 0.918066] usb usb1: SerialNumber: musb-hdrc.0.auto
[ 0.919313] hub 1-0:1.0: USB hub found
[ 0.919400] hub 1-0:1.0: 1 port detected
[ 0.922574] 47401b00.usb-phy supply vcc not found, using dummy regulator
[ 0.925744] musb-hdrc: ConfigData=0xde (UTMI-8, dyn FIFOs, bulk combine, bulk split, HB-ISO Rx, HB-ISO Tx, SoftConn)
[ 0.925773] musb-hdrc: MHDRC RTL version 2.0
[ 0.925785] musb-hdrc: setup fifo_mode 4
[ 0.925811] musb-hdrc: 28/31 max ep, 16384/16384 memory
[ 0.925986] musb-hdrc musb-hdrc.1.auto: MUSB HDRC host driver
[ 0.926028] musb-hdrc musb-hdrc.1.auto: new USB bus registered, assigned bus number 2
[ 0.926376] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002
[ 0.926393] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 0.926405] usb usb2: Product: MUSB HDRC host driver
[ 0.926417] usb usb2: Manufacturer: Linux 4.4.113-ti-xenomai-r149 musb-hcd
[ 0.926429] usb usb2: SerialNumber: musb-hdrc.1.auto
[ 0.927652] hub 2-0:1.0: USB hub found
[ 0.927728] hub 2-0:1.0: 1 port detected
[ 0.940194] mousedev: PS/2 mouse device common for all mice
[ 0.943928] omap_rtc 44e3e000.rtc: rtc core: registered 44e3e000.rtc as rtc0
[ 0.945608] i2c /dev entries driver
[ 0.948209] omap_wdt: OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec
[ 0.949862] omap_hsmmc 48060000.mmc: Got CD GPIO
[ 0.982101] pinctrl-single 44e10800.pinmux: pin 44e10830.0 already requested by ocp:P2_24_pinmux; cannot claim for bela_digitals
[ 0.993997] pinctrl-single 44e10800.pinmux: pin-12 (bela_digitals) status -22
[ 1.001303] pinctrl-single 44e10800.pinmux: could not request pin 12 (44e10830.0) from group pinmux_bb_digitals on device pinctrl-single
[ 1.014810] leds-gpio bela_digitals: Error applying setting, reverse things back
[ 1.030835] hidraw: raw HID events driver (C) Jiri Kosina
[ 1.031765] usbcore: registered new interface driver usbhid
[ 1.031782] usbhid: USB HID core driver
[ 1.032180] ashmem: initialized
[ 1.033570] remoteproc0: wkup_m3 is available
[ 1.033594] remoteproc0: Note: remoteproc is still under development and considered experimental.
[ 1.033605] remoteproc0: THE BINARY FORMAT IS NOT YET FINALIZED, and backward compatibility isn't yet guaranteed.
[ 1.039587] NET: Registered protocol family 10
[ 1.041341] mip6: Mobile IPv6
[ 1.041379] NET: Registered protocol family 17
[ 1.041553] Key type dns_resolver registered
[ 1.041572] mpls_gso: MPLS GSO support
[ 1.041913] omap_voltage_late_init: Voltage driver support not added
[ 1.049592] PM: Cannot get wkup_m3_ipc handle
[ 1.054182] ThumbEE CPU extension supported.
[ 1.055460] registered taskstats version 1
[ 1.055661] zswap: loaded using pool lzo/zbud
[ 1.060500] Btrfs loaded
[ 1.062682] Key type encrypted registered
[ 1.067244] input: tps65217_pwr_but as /devices/platform/ocp/44e0b000.i2c/i2c-0/0-0024/input/input0
[ 1.092207] mmc0: host does not support reading read-only switch, assuming write-enable
[ 1.093396] tps65217 0-0024: TPS65217 ID 0xe version 1.2
[ 1.094183] at24 0-0050: 32768 byte 24c256 EEPROM, writable, 1 bytes/write
[ 1.094251] omap_i2c 44e0b000.i2c: bus 0 rev0.11 at 400 kHz
[ 1.094655] mmc0: new high speed SDHC card at address e624
[ 1.097484] omap_i2c 4802a000.i2c: bus 1 rev0.11 at 100 kHz
[ 1.098465] mmcblk0: mmc0:e624 SU04G 3.69 GiB
[ 1.100925] PM: bootloader does not support rtc-only!
[ 1.102173] omap_rtc 44e3e000.rtc: setting system clock to 2000-01-01 00:00:00 UTC (946684800)
[ 1.102209] of_cfs_init
[ 1.102367] of_cfs_init: OK
[ 1.104614] mmcblk0: p1 p2
[ 1.106177] remoteproc0: powering up wkup_m3
[ 1.106209] remoteproc0: Booting fw image am335x-pm-firmware.elf, size 217148
[ 1.106491] remoteproc0: remote processor wkup_m3 is now up
[ 1.106529] wkup_m3_ipc 44e11324.wkup_m3_ipc: CM3 Firmware Version = 0x192
[ 1.113341] PM: Hibernation image not present or could not be loaded.
[ 1.118993] EXT4-fs (mmcblk0p2): INFO: recovery required on readonly filesystem
[ 1.119023] EXT4-fs (mmcblk0p2): write access will be enabled during recovery
[ 1.316403] usb 2-1: new full-speed USB device number 2 using musb-hdrc
[ 1.445727] usb 2-1: New USB device found, idVendor=0483, idProduct=5730
[ 1.445749] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1.445761] usb 2-1: Product: Pyramid MIDI USB
[ 1.445773] usb 2-1: Manufacturer: Squarp Instruments
[ 1.445784] usb 2-1: SerialNumber: 396F34593036
[ 2.535541] EXT4-fs (mmcblk0p2): recovery complete
[ 2.853250] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[ 2.853380] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.
[ 2.854436] devtmpfs: mounted
[ 2.855052] Freeing unused kernel memory: 456K
[ 3.200546] systemd[1]: System time before build time, advancing clock.
[ 3.278590] ip_tables: (C) 2000-2006 Netfilter Core Team
[ 3.314814] random: systemd: uninitialized urandom read (16 bytes read, 35 bits of entropy available)
[ 3.318514] random: systemd: uninitialized urandom read (16 bytes read, 35 bits of entropy available)
[ 3.332140] systemd[1]: systemd 232 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN)
[ 3.333135] systemd[1]: Detected architecture arm.
[ 3.337030] systemd[1]: Set hostname to <bela>.
[ 3.546470] random: systemd-sysv-ge: uninitialized urandom read (16 bytes read, 37 bits of entropy available)
[ 3.563997] random: systemd-cryptse: uninitialized urandom read (16 bytes read, 38 bits of entropy available)
[ 3.577677] random: systemd-gpt-aut: uninitialized urandom read (16 bytes read, 38 bits of entropy available)
[ 3.578232] random: systemd-gpt-aut: uninitialized urandom read (16 bytes read, 38 bits of entropy available)
[ 3.709165] random: systemd: uninitialized urandom read (16 bytes read, 44 bits of entropy available)
[ 3.709480] random: systemd: uninitialized urandom read (16 bytes read, 44 bits of entropy available)
[ 3.709884] random: systemd: uninitialized urandom read (16 bytes read, 44 bits of entropy available)
[ 3.710600] random: systemd: uninitialized urandom read (16 bytes read, 44 bits of entropy available)
[ 3.975580] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[ 3.976633] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe.
[ 3.976939] systemd[1]: Reached target Remote File Systems.
[ 3.977446] systemd[1]: Listening on udev Kernel Socket.
[ 3.977667] systemd[1]: Reached target Swap.
[ 3.978033] systemd[1]: Listening on fsck to fsckd communication Socket.
[ 3.979785] systemd[1]: Created slice System Slice.
[ 3.985975] systemd[1]: Mounting POSIX Message Queue File System...
[ 3.988010] systemd[1]: Created slice system-getty.slice.
[ 3.993250] systemd[1]: Listening on udev Control Socket.
[ 3.993894] systemd[1]: Listening on Journal Socket (/dev/log).
[ 3.995060] systemd[1]: Listening on Journal Audit Socket.
[ 4.025607] systemd[1]: Mounting Debug File System...
[ 4.026484] systemd[1]: Listening on Syslog Socket.
[ 4.027423] systemd[1]: Started Dispatch Password Requests to Console Directory Watch.
[ 4.027754] systemd[1]: Reached target Paths.
[ 4.027985] systemd[1]: Reached target Encrypted Volumes.
[ 4.062120] systemd[1]: Created slice User and Session Slice.
[ 4.062517] systemd[1]: Reached target Slices.
[ 4.064151] systemd[1]: Created slice system-systemd\x2dfsck.slice.
[ 4.078522] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point.
[ 4.098358] systemd[1]: Created slice system-serial\x2dgetty.slice.
[ 4.099191] systemd[1]: Listening on Journal Socket.
[ 4.182022] systemd[1]: Starting Journal Service...
[ 4.231224] systemd[1]: Starting Load Kernel Modules...
[ 4.322723] systemd[1]: Starting File System Check on Root Device...
[ 4.391088] systemd[1]: Starting Create list of required static device nodes for the current kernel...
[ 4.529077] rtdm_pruss_irq: loading out-of-tree module taints kernel.
[ 4.530014] rtdm_pruss_irq version 1 loaded
[ 4.572300] systemd[1]: Mounted POSIX Message Queue File System.
[ 4.602580] systemd[1]: Mounted Debug File System.
[ 4.635521] systemd[1]: Started Load Kernel Modules.
[ 4.663590] systemd[1]: Started Create list of required static device nodes for the current kernel.
[ 4.758255] systemd[1]: Started File System Check Daemon to report status.
[ 4.798730] systemd[1]: Starting Create Static Device Nodes in /dev...
[ 4.944991] systemd[1]: Starting Apply Kernel Variables...
[ 4.987458] systemd[1]: Mounting Configuration File System...
[ 5.126585] systemd[1]: Mounting FUSE Control File System...
[ 5.328746] systemd[1]: Started File System Check on Root Device.
[ 5.331803] systemd[1]: Started Create Static Device Nodes in /dev.
[ 5.366452] systemd[1]: Started Apply Kernel Variables.
[ 5.367938] systemd[1]: Mounted Configuration File System.
[ 5.392035] systemd[1]: Mounted FUSE Control File System.
[ 5.489411] systemd[1]: Starting udev Kernel Device Manager...
[ 5.545989] systemd[1]: Starting Remount Root and Kernel File Systems...
[ 5.640061] systemd[1]: Started Journal Service.
[ 5.742662] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[ 6.170270] systemd-journald[99]: Received request to flush runtime journal from PID 1
[ 8.632051] usbcore: registered new interface driver snd-usb-audio
[ 8.714758] CAN device driver interface
[ 8.759872] c_can_platform 481cc000.can: c_can_platform device registered (regs=fa1cc000, irq=167)
[ 8.800717] c_can_platform 481d0000.can: c_can_platform device registered (regs=fa1d0000, irq=168)
[ 8.869260] omap_rng 48310000.rng: OMAP Random Number Generator ver. 20
[ 9.754760] omap-sham 53100000.sham: hw accel on OMAP rev 4.3
[ 9.937989] omap-aes 53500000.aes: OMAP AES hw accel rev: 3.2
[ 11.454236] pinctrl-single 44e10800.pinmux: pin 44e10828.0 already requested by ocp:P1_34_pinmux; cannot claim for spi_gpio
[ 11.597558] using random self ethernet address
[ 11.597595] using random host ethernet address
[ 11.711861] using random self ethernet address
[ 11.711898] using random host ethernet address
[ 11.841747] Mass Storage Function, version: 2009/09/11
[ 11.841786] LUN: removable file: (no medium)
[ 11.883057] pinctrl-single 44e10800.pinmux: pin-10 (spi_gpio) status -22
[ 11.898571] random: nonblocking pool is initialized
[ 11.986880] pinctrl-single 44e10800.pinmux: could not request pin 10 (44e10828.0) from group pinmux_bb_spi_gpio_pins on device pinctrl-single
[ 12.181752] spi_gpio spi_gpio: Error applying setting, reverse things back
[ 12.298328] spi_gpio: probe of spi_gpio failed with error -16
[ 13.418727] ti_am3359-tscadc 44e0d000.tscadc: chan 0 step_avg truncating to 16
[ 13.418765] ti_am3359-tscadc 44e0d000.tscadc: chan 1 step_avg truncating to 16
[ 13.418779] ti_am3359-tscadc 44e0d000.tscadc: chan 2 step_avg truncating to 16
[ 13.418792] ti_am3359-tscadc 44e0d000.tscadc: chan 3 step_avg truncating to 16
[ 13.418805] ti_am3359-tscadc 44e0d000.tscadc: chan 4 step_avg truncating to 16
[ 13.418817] ti_am3359-tscadc 44e0d000.tscadc: chan 5 step_avg truncating to 16
[ 13.418830] ti_am3359-tscadc 44e0d000.tscadc: chan 6 step_avg truncating to 16
[ 13.418842] ti_am3359-tscadc 44e0d000.tscadc: chan 7 step_avg truncating to 16
[ 14.467936] usb0: HOST MAC be:1a:05:f5:37:84
[ 14.470134] usb0: MAC be:1a:05:f5:37:85
[ 14.476592] usb1: HOST MAC be:1a:05:f5:37:87
[ 14.476996] usb1: MAC be:1a:05:f5:37:88
[ 14.751895] configfs-gadget gadget: high-speed config #1: c
[ 17.716672] IPv6: ADDRCONF(NETDEV_UP): usb1: link is not ready
[ 20.879582] rtdm_pruss_irq_open
[ 20.880100] Registering PRU interrupt:
PRU ICSS system event: 20
PRU INTC channel: 4
PRU INTC host interrupt: 4
ARM IRQ number: 22
[ 20.880127] rtdm_pruss_irq linux_irq: 181 for arm_irq_handle_number: 22
[ 20.880137] INITING_PRU: system_event: 20, intc_channel: 4, intc_host: 4
[ 20.880145] : 0XD00 = 0XFFFFFFFF [u32]
[ 20.880153] : 0XD04 = 0XFFFFFFFF [u32]
[ 20.880160] : 0XD80 = 0X0 [u32]
[ 20.880168] : 0XD84 = 0X0 [u32]
[ 20.880176] cmr_reg
[ 20.880185] : 0X414 = 0X4 [u8]
[ 20.880192] hmr_reg
[ 20.880198] : 0X804 = 0X4 [u8]
[ 20.880205] secr0
[ 20.880212] : 0X280 = 0XFFFFFFFF [u32]
[ 20.880219] secr1
[ 20.880225] : 0X284 = 0XFFFFFFF [u32]
[ 20.880232] eisr_reg
[ 20.880239] : 0X28 = 0X14 [u32]
[ 20.880246] hieisr_reg
[ 20.880252] : 0X34 = 0X4 [u32]
[ 20.880259] hier
[ 20.880265] hier read: 10
[ 20.880272] esr0
[ 20.880295] : 0X300 = 0X100000 [u32]
[ 20.880303] intc_ger
[ 20.880309] : 0X10 = 0X1 [u32]
[ 111.468935] usb 2-1: USB disconnect, device number 2
[ 115.408464] usb 2-1: new full-speed USB device number 3 using musb-hdrc
[ 115.538584] usb 2-1: New USB device found, idVendor=0483, idProduct=5730
[ 115.538639] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 115.538652] usb 2-1: Product: Pyramid MIDI USB
[ 115.538664] usb 2-1: Manufacturer: Squarp Instruments
[ 115.538676] usb 2-1: SerialNumber: 396F34593036
[ 121.823347] usb 2-1: USB disconnect, device number 3
[ 123.852524] usb 2-1: new full-speed USB device number 4 using musb-hdrc
[ 123.982753] usb 2-1: New USB device found, idVendor=0483, idProduct=5730
[ 123.982787] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 123.982800] usb 2-1: Product: Pyramid MIDI USB
[ 123.982812] usb 2-1: Manufacturer: Squarp Instruments
[ 123.982824] usb 2-1: SerialNumber: 396F34593036
You can see at the end here, I unplugged and plugged in the USB A cable twice and it recognizes it both times as a "new full-speed USB device".
Let me know if this provides any additional explanation - in terms of whether this is an inherent issue with the Bela Mini, I'm somehow missing some code needed to get the USB A recognized when powered via VIN, or if my specific unit is broken / damaged.