Not able to create more than 7 partitions on the am335x(beaglebone black) based custom board

Ankur Tank

I am trying to partition eMMC of BBB(am335x) based custom board, I am using sfdisk to do that. I am using following command to do that,

#Partition emmc 
sfdisk -D -H 255 -S 63 -C 467 /dev/mmcblk0 -uM << EOF
,32,C,*
,200,L
,200,L
,,E
,100,L
,60,L
,200,L
;1269,L
;
EOF

But sfdisk shows following partitions and

# fdisk -l /dev/mmcblk0

Disk /dev/mmcblk0: 3841 MB, 3841982464 bytes
255 heads, 63 sectors/track, 467 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

        Device Boot      Start         End      Blocks  Id System
/dev/mmcblk0p1   *           1           5       40131   c Win95 FAT32 (LBA)
/dev/mmcblk0p2               6          31      208845  83 Linux
/dev/mmcblk0p3              32          57      208845  83 Linux
/dev/mmcblk0p4              58         467     3293325   5 Extended
/dev/mmcblk0p5              58          70      104391  83 Linux
/dev/mmcblk0p6              71          78       64228+ 83 Linux
/dev/mmcblk0p7              79         104      208813+ 83 Linux
/dev/mmcblk0p8             105         266     1301233+ 83 Linux
/dev/mmcblk0p9             267         467     1614501  83 Linux

but I don't see /dev/mmcblk0p8 and /dev/mmcblk0p9. Because of that i am not able to format the /dev/mmcblk0p8. Can anyone suggest what could be the problem ?

is there a limit on creating extended partitions ?

over 9 years ago

0 Titusrathinaraj Stalin over 9 years ago

TI__Guru** 116100 points

Hi Ankur,
Do you have "SD card" or "USB" interface in your board ?
If yes, you can follow the same command for that 4GiB SD card and check it.
Also, you can try the same command in PC for 4GiB SD card/USB.

0 Ankur Tank over 9 years ago in reply to Titusrathinaraj Stalin

Expert 2985 points

HI Titus,
I was expecting first reply form you only :)
Thank you for reply,

Unfortunately I don't have SD card or USB interface :(

Regards,
Ankur

0 Titusrathinaraj Stalin over 9 years ago in reply to Ankur Tank

TI__Guru** 116100 points

Provide the logs when you use that command in your board.

0 Ankur Tank over 9 years ago in reply to Titusrathinaraj Stalin

Expert 2985 points

# sfdisk -D -H 255 -S 63 -C 467 /dev/mmcblk0 -uM << EOF
> ,32,C,*
> ,200,L
> ,200,L
> ,,E
> ,100,L
> ,60,L
> ,200,L
> ;1269,L
> ;
> EOF
Checking that no-one is using this disk right now ...
[ 4889.774695]  mmcblk0: p1 p2 p3 p4 < p5 p6 p7 >
OK

Disk /dev/mmcblk0: 467 cylinders, 255 heads, 63 sectors/track
Old situation:
Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start   End    MiB    #blocks   Id  System
/dev/mmcblk0p1   *     0+    39-    40-     40131    c  W95 FAT32 (LBA)
/dev/mmcblk0p2        39+   243-   204-    208845   83  Linux
/dev/mmcblk0p3       243+   447-   204-    208845   83  Linux
/dev/mmcblk0p4       447+  3663-  3217-   3293325    5  Extended
/dev/mmcblk0p5       447+   549-   102-    104391   83  Linux
/dev/mmcblk0p6       549+   611-    63-     64228+  83  Linux
/dev/mmcblk0p7       611+   815-   204-    208813+  83  Linux
/dev/mmcblk0p8       815+  2086-  1271-   1301233+  83  Linux
/dev/mmcblk0p9      2086+  3663-  1577-   1614501   83  Linux
New situation:
Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start   End    MiB    #blocks   Id  System
/dev/mmcblk0p1   *     0+    39-    40-     40131    c  W95 FAT32 (LBA)
/dev/mmcblk0p2        39+   243-   204-    208845   83  Linux
/dev/mmcblk0p3       243+   447-   204-    208845   83  Linux
/dev/mmcblk0p4       447+  3663-  3217-   3293325    5  Extended
/dev/mmcblk0p5       447+   549-   102-    104391   83  Linux
/dev/mmcblk0p6       549+   611-    63-     64228+  83  Linux
/dev/mmcblk0p7       611+   815-   204-    208813+  83  Linux
/dev/mmcblk0p8       815+  2086-  1271-   1301233+  83  Linux
/dev/mmcblk0p9      2086+  3663-  1577-   1614501   83  Linux
Successfully wrote the new partition table

Re-reading the partition table ...
[ 4890.031774]  mmcblk0: p1 p2 p3 p4 < p5 p6 p7 >

If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
to zero the first 512 bytes:  dd if=/dev/zero of=/dev/foo7 bs=512 count=1
(See fdisk(8).)

Here it is.
Actually sfdisk also reports 7 partitions instead of 8/9 :(

0 Titusrathinaraj Stalin over 9 years ago in reply to Ankur Tank

TI__Guru** 116100 points

Hi Ankur,
The command seems good,
I've tried on my linux machine for 4GiB SD card and got the following, also able to mount all the partitions.

Checking that no-one is using this disk right now ...
[ 4889.774695] mmcblk0: p1 p2 p3 p4 < p5 p6 p7 >

It seems, the print is from kernel, so we may need to look into kernel too.

What is the "sfdisk" command version ?

On my Linux machine:

ti@e2e:~/test$ sfdisk --version
sfdisk from util-linux 2.20.1

Log:

ti@e2e:~/test$ sudo sfdisk -D -H 255 -S 62 -C 1023 /dev/sdd -uM << EOF
> ,32,C,*
> ,200,L
> ,200,L
> ,,E
> ,100,L
> ,60,L
> ,200,L
> ;1269,L
> ;
> EOF
Checking that no-one is using this disk right now ...
OK

Disk /dev/sdd: 1023 cylinders, 255 heads, 62 sectors/track
Old situation:
Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0

Device Boot Start End MiB #blocks Id System
/dev/sdd1 0 - 0 0 0 Empty
/dev/sdd2 0 - 0 0 0 Empty
/dev/sdd3 0 - 0 0 0 Empty
/dev/sdd4 0 - 0 0 0 Empty
New situation:
Units = mebibytes of 1048576 bytes, blocks of 1024 bytes, counting from 0

Device Boot Start End MiB #blocks Id System
/dev/sdd1 * 0+ 38- 39- 39494 c W95 FAT32 (LBA)
/dev/sdd2 38+ 239- 201- 205530 83 Linux
/dev/sdd3 239+ 440- 201- 205530 83 Linux
/dev/sdd4 440+ 3774- 3335- 3414960 5 Extended
/dev/sdd5 440+ 540- 101- 102734 83 Linux
/dev/sdd6 540+ 602- 62- 63209 83 Linux
/dev/sdd7 602+ 802- 201- 205499 83 Linux
/dev/sdd8 802+ 2076- 1274- 1304294 83 Linux
/dev/sdd9 2076+ 3774- 1699- 1739069 83 Linux
Successfully wrote the new partition table

Re-reading the partition table ...

If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
to zero the first 512 bytes: dd if=/dev/zero of=/dev/foo7 bs=512 count=1
(See fdisk(8).)
ti@e2e:~/test$
ti@e2e:~/test$
ti@e2e:~/test$
ti@e2e:~/test$
ti@e2e:~/test$ sudo fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0004d7a6

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 148123647 74060800 83 Linux
/dev/sda2 148125694 156301311 4087809 5 Extended
/dev/sda5 148125696 156301311 4087808 82 Linux swap / Solaris

Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0000e2a7

Device Boot Start End Blocks Id System
/dev/sdb1 2048 957241343 478619648 83 Linux
/dev/sdb2 957243390 976771071 9763841 5 Extended
/dev/sdb5 957243392 976771071 9763840 82 Linux swap / Solaris

Disk /dev/sdd: 3965 MB, 3965190144 bytes
255 heads, 62 sectors/track, 489 cylinders, total 7744512 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000c2719

Device Boot Start End Blocks Id System
/dev/sdd1 * 62 79049 39494 c W95 FAT32 (LBA)
/dev/sdd2 79050 490109 205530 83 Linux
/dev/sdd3 490110 901169 205530 83 Linux
/dev/sdd4 901170 7731089 3414960 5 Extended
/dev/sdd5 901232 1106699 102734 83 Linux
/dev/sdd6 1106762 1233179 63209 83 Linux
/dev/sdd7 1233242 1644239 205499 83 Linux
/dev/sdd8 1644302 4252889 1304294 83 Linux
/dev/sdd9 4252952 7731089 1739069 83 Linux
ti@e2e:~/test$

0 Ankur Tank over 9 years ago in reply to Titusrathinaraj Stalin

Expert 2985 points

Hi Titus,

Thank you for reply,
My sfdisk version "sfdisk from util-linux 2.21.2" which seems to be latest. :)
Partitions are fine but are you able to format the file system on the /dev/sdd9 and mount the same ?

Thank you,

Regards,
Ankur

0 Ankur Tank over 9 years ago in reply to Ankur Tank

Expert 2985 points

Thanks to Robert C Nelson who replied my query on Beaglebone black community.
One of the configuration, MMC_BLOCK_MINORS [=8] was set to 8 which was preventing driver to create more than 8 device files. I changed number and i am able to see all the partitions and respective device files.

Location:
│ -> Device Drivers
│ -> MMC/SD/SDIO card support (MMC [=y])
│ -> MMC block device driver (MMC_BLOCK [=y])

Hope this helps some having same problem.

0 Titusrathinaraj Stalin over 9 years ago in reply to Ankur Tank

TI__Guru** 116100 points

Hi Ankur,
Sounds good.
Thanks for your update.

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Not able to create more than 7 partitions on the am335x(beaglebone black) based custom board