only 256MB memory on BeagleBone Black

[sig6247]

Hi,

I'm running the image that downloaded from
http://www.minix3.org/download/minix_arm_sd_beaglebones-3.3.0.img.bz2

# cat /proc/meminfo
4096 65547 48097 27825 9001

The total memory is only 4096*65547/1024 = 262188K

It seems this board has 512 MB memory ...
------------------------------------------------
U-Boot 2013.04-dirty (Jul 10 2013 - 14:02:53)

I2C: ready
DRAM: 512 MiB
WARNING: Caches not enabled
NAND: No NAND device found!!!
0 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - readenv() failed, using default environment
------------------------------------------------

Thanks,

[webf...@web.de]

Hi,

I get the same numbers, even "top" says 256MB total memory...
Maybe that is because the image is also for the BB White, which has only 256MB RAM.

Regards,
Frank

[webf...@web.de]

Hi again,

Looks like the memory is hardcoded in the kernel.

In the source file src/minix/kernel/arch/earm/pre_init.c you find the following lines:

/* XXX: hard-coded stuff for modules */

#define MB_MODS_NR NR_BOOT_MODULES

#define MB_MODS_BASE  0x82000000

#define MB_MODS_ALIGN 0x00800000 /* 8 MB */

#define MB_MMAP_START 0x80000000

#define MB_MMAP_SIZE  0x10000000 /* 256 MB */

If you change the last line to

#define MB_MMAP_SIZE  0x20000000 /* 1=256 MB   2=512MB */

and rebuild the kernel, you get the full 512MB on the BB Black.

(I assume you can't use that kernel anymore on a 256MB board then...)

top shows for me now:

load averages:  0.11, 0.22, 0.07

45 processes: 1 running, 44 sleeping

main memory: 524332K total, 453312K free, 371216K contig free, 36156K cached

CPU states:   2.93% user,   3.40% system,  17.72% kernel,  75.95% idle

CPU time displayed ('t' to cycle): user ;  sort order ('o' to cycle): cpu

Regards,

Frank

[sig6247]

Hi Frank,

Yes, it worked. Thanks.