Raspberry PI sporadically fails to mount mmc card

Hi,

Sporadically the raspberry pi fails to mount its root mmc card. After power
off and power on again it works most of the time. However there seem to be
also configurations that fail permanently. Unfortunately I have no image of
a sd card that fails on every boot.
Do you have any idea how to get more information whats going wrong? I think
the problem starts after mmcsd0 received a timeout. Before that there are
three lock reversals but I am not sure if they have any connection to the
timeouts:


lock order reversals before the timeout:


 1st 0xc06f3c0c entropy harvest mutex (entropy harvest mutex) _at_
/usr/home/martin/Rasperry/head/sys/dev/random/randomdev_soft.c:242
 2nd 0xc25d7c20 uart_hwmtx (uart_hwmtx) _at_
/usr/home/martin/Rasperry/head/sys/dev/uart/uart_cpu.h:92

 1st 0xc06f3c0c entropy harvest mutex (entropy harvest mutex) _at_
/usr/home/martin/Rasperry/head/sys/dev/random/randomdev_soft.c:242
 2nd 0xc059198c sleepq chain (sleepq chain) _at_
/usr/home/martin/Rasperry/head/sys/kern/subr_sleepqueue.c:240

 1st 0xc06f3c0c entropy harvest mutex (entropy harvest mutex) _at_
/usr/home/martin/Rasperry/head/sys/dev/random/randomdev_soft.c:242
 2nd 0xc059198c sleepq chain (sleepq chain) _at_
/usr/home/martin/Rasperry/head/sys/kern/subr_sleepqueue.c:240



[...]
usbus0: 480Mbps High Speed USB v2.0
ugen0.1: <DWCOTG> at usbus0
uhub0: <DWCOTG OTG Root HUB, class 9/0, rev 2.00/1.00, addr 1> on usbus0
uhub0: 1 port with 1 removable, self powered
mmcsd0: 8GB <SDHC NCard 1.0 SN 1075839384 MFG 05/2013 by 130 JT> at mmc0
50.0MHz/4bit/65535-block
WARNING: WITNESS option enabled, expect reduced performance.
WARNING: DIAGNOSTIC option enabled, expect reduced performance.
mmcsd0: Error indicated: 1 Timeout
mmcsd0: Error indicated: 1 Timeout
Root mount waiting for: usbus0
ugen0.2: <vendor 0x0424> at usbus0
uhub1: <vendor 0x0424 product 0x9512, class 9/0, rev 2.00/2.00, addr 2> on
usbus0
uhub1: MTT enabled
Root mount waiting for: usbus0
uhub1: 3 ports with 2 removable, self powered
Root mount waiting for: usbus0
ugen0.3: <vendor 0x0424> at usbus0
smsc0: <vendor 0x0424 product 0xec00, rev 2.00/2.00, addr 3> on usbus0
Trying to mount root from ufs:/dev/mmcsd0s2a [rw,noatime]...
mountroot: waiting for device /dev/mmcsd0s2a ...
smsc0: chip 0xec00, rev. 0002
miibus0: <MII bus> on smsc0
ukphy0: <Generic IEEE 802.3u media interface> PHY 1 on miibus0
ukphy0:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
ue0: <USB Ethernet> on smsc0
ue0: Ethernet address: b8:27:eb:1d:b7:5a
Mounting from ufs:/dev/mmcsd0s2a failed with error 19.

Loader variables:
  vfs.root.mountfrom=ufs:/dev/mmcsd0s2a
  vfs.root.mountfrom.options=rw,noatime

Manual root filesystem specification:
  <fstype>:<device> [options]
      Mount <device> using filesystem <fstype>
      and with the specified (optional) option list.

    eg. ufs:/dev/da0s1a
        zfs:tank
        cd9660:/dev/acd0 ro
          (which is equivalent to: mount -t cd9660 -o ro /dev/acd0 /)

  ?               List valid disk boot devices
  .               Yield 1 second (for background tasks)
  <empty line>    Abort manual input

mountroot>


For details and the full boot log have a look to:

http://www.freebsd.org/cgi/query-pr.cgi?pr=181601

Best regards,
 Martin Laabs