Nitrogen6x, imx6 Android 4.2.2, how to mount mmc1?

[blauer]

Hello,

we use the SabreLite board and boot with Android 4.2.2. Whe I plut in my SD card I can see the message on the console: mmc1 new high speed SDHC card at address 0001. But the card is not mounted. I have no access. What modifications do we have to do at the Android sources to have access on the application side?

[EricNelson]

Hi Michael,

We've been looking into this, and it's not clear what the problem is.

We fixed USB mounting in our latest 4.3 build, and made some strides with the alternate SD card as well:

          http://boundarydevices.com/bluetooth-on-jellybean/

In that release, two patches were needed to fix USB stick mounting.

This one implements the proper paths needed because we have a USB hub on SABRE Lite and
Nitrogen6x:

     nitrogen6x: fix USB mount points for vold · 78da1e8 · boundarydevices/android_device_boundary ·...

And this one adds a USB permissions file to allow applications to access the mount point:

     nitrogen6x: add USB host permissions file · 5dfb2b4 · boundarydevices/android_device_boundary · GitH...

The SD card bit is a bit tougher to crack, since we added support for booting to either SD card or SATA:

     http://boundarydevices.com/android-jellybean-on-i-mx6-with-no-disclaimers/#sata

At a minimum, we'll need to choose one of the two SD cards and configure vold.fstab to have the proper

references. The default file specifies the top slot, but doesn't yet function:

      android_device_boundary/nitrogen6x/vold.fstab at boundary-imx_jb4.3_1.0.0-ga · boundarydevices/andro...

[EricNelson]

Hi Michael,

I figured this out, with help from this post:

     Support Two USB Disks through USB Hub in Android

The trick is actually in fstab.boundary. This file has a line that reads like this:

$BD1 /mnt/extsd vfat defaults voldmanaged=sdcard:auto

This is apparently used by the storage manager to know about /mnt/extsd.

The $BD1 is replaced at run-time by our change to the system mounting code to the boot device based on where the boot script was found, and so this is intentionally wrong.

It should actually point to the other SD card slot, but we don't yet have support for that.

I just pushed a patch that adds comments and two examples for using one or the other slot on Nitrogen6x or SABRE Lite. If you incorporate this into your build and choose one, you should see the disk mounted when inserted:

     nitrogen6x: add comments/examples about extsd mount point · 5f48a09 · boundarydevices/android_device...

Regards,

Eric