Hi,
> > ...
> > fw_setenv state=2
> > dd if=... of=/dev/mmcblk0...
> > fw_setenv state=1
> > ...
> > reboot
>
> Not sure what final "OS" environment you're running, but I would think
> that "reboot" would sync for you ?
I'm using OpenWRT and reboot links to the busybox implementation.
This implemenetation calls sync when I traced it correctly.
According to "man 2 sync":
<quote>
DESCRIPTION
sync() causes all buffered modifications to file metadata and data to be
written to the underlying file systems.
</quote>
When I use fw_setenv with /dev/mmcblk0, that means with a block device directly,
then I have a problem matching the "filesystem layer" of the description above
with
the "block layer" which I am using.
Futhermore another quote from the very same man page:
<quote>
BUGS
...sync() schedules the writes, but may return before the actual writing
is done. However, since version 1.3.20 Linux
does actually wait. (This still does not guarantee data integrity:
modern disks have large caches.)
</quote>
So it seems to me, that calling "sync" doesn't do the job.
When looking at "man 2 fsync" I read
<quote>
... This includes writing through or flushing a disk cache if
present. The call blocks until the device reports that the transfer has
completed....
</quote>
This looks much better.
However, I did not trace the call chain in linux kernel down to the block layer
yet.
Maybe I should.
BR, Michael
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
