On 12/14/2014 07:52 AM, Iain Paton wrote:
Set ptuuid and fsuuid variables to the partition / filesystem where we found extlinux.conf which allows us to use a replaceable parameter in the append line in extlinux.conf like this
append root=PARTUUID=${ptuuid}
this means we never have to hardcode a root=/dev/mmcblk0p1 type path anywhere.
Wouldn't the distro/... that creates extlinux.conf simply put the UUID into the file when it's generated? That's how things normally work in similar setups such as grub.conf...
Since the uuids are only looked for after we've already found extlinux.conf there's little cost/risk to making them available. I realise that assuming extlinux.conf is on the root partition isn't perfect but for the common case where it will be, there are many advantages to this.
... and completely avoids the issue of U-Boot making assumptions about the partition layout that the distro installer used.