Why can't I see eMMC device from Linux 3.8?

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1

I’ve got a beagle bone black which is booting a self built 3.8 kernel over TFTP / NFS. The kernel source is from (https://github.com/beagleboard/linux.git). For some reason, I am not able to see a mmc block device assigned. The cape manager sees it and assigns it to a slot. But ls -l /sys/bus/mmc/devices does not show anything.

However, if I insert a SD card, I am able to see a block mmc device assigned for it. I would like to be able to mount the eMMC device.

Am I missing something? I was assuming that both the eMMC and the SD would have corresponding mmc block devices assigned by the driver.

2

Could someone at least confirm that I should be able to see device files /dev/mmc0* and /dev/mmc1* for both the eMMC and an SD card assuming both are present? It seems like the 3.8 kernel is playing hanky panky with these mmc devices.

3

Could someone at least confirm that I should be able to see device files /dev/mmc0* and /dev/mmc1* for both the eMMC and an SD card assuming both are present? It seems like the 3.8 kernel is playing hanky panky with these mmc devices.

root@beaglebone:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
mmcblk1boot0 179:16 0 1M 1 disk
mmcblk1boot1 179:24 0 1M 1 disk
mmcblk0 179:0 0 3.7G 0 disk
`-mmcblk0p1 179:1 0 1.7G 0 part /
mmcblk1 179:8 0 1.8G 0 disk

-mmcblk1p1 179:9 0 70.6M 0 part
`-mmcblk1p2 179:10 0 1.7G 0 part
root@beaglebone:~# uname -a
Linux beaglebone 3.14.26-ti-r39 #1 SMP PREEMPT Mon Dec 8 04:56:09 UTC 2014 armv7l GNU/Linux

So, it is /dev/mmcblkX not /dev/mmcX, anyway ls -l /sys/bus/mmc/devices works fine n this end, I’d say you have a problem. Exactly what ? No idea . . .

4

And yeah, this is for 3.14.x, but I’d get the same result for 3.8.x as well. . .

5

Thanks for confirming William. Yeah it was working on 3.14 for me also. I had too many other problems with 3.14 (mainly SPI devices) and had to revert back to 3.8. Now I am seeing this oddity.

6

Try using one of Robert’s older rootfs’s, and maybe an older kernel. I’m personally still using *bone47. But this one I am setting up to show someone how to get something done . . .except now I can not remember what . . .heh

7

I actually gave the newer 3.14 kernel another try today. It has been about 4 months since my last attempt. This time success! I am able to see all the MMC device files and also the SPI devices are working like a champ, which they weren’t 4 months ago. Case closed. I’ll be sticking with 3.14 unless I run into any new problems.