On 01/07/2015 03:10 AM, Sjoerd Simons wrote:
On Tue, 2015-01-06 at 17:43 -0700, Stephen Warren wrote:
(CCing Dennis so he can comment from a distro perspective re: partition
table bootable flags v.s. scanning all partitions)
On 01/06/2015 10:07 AM, Sjoerd Simons wrote:
On Mon, 2015-01-05 at 13:24 -0700, Stephen Warren wrote:
On 01/05/2015 10:13 AM, Sjoerd Simons wrote:
Well my thoughts on the matter are above, If folks feel strongly about
this approach being the wrong way I'd love to hear their arguments :).
One issue with this approach is that there's no way for the user to
short-circuit the scanning. If I put a ChromiumOS install on an SD card
and leave it plugged into a system that's going to end up booting from
eMMC since that's where the boot files are, there are lots of partitions
to scan on that SD card, which will be a bit annoying.
I don't remember exactly how many partitions with fat/ext* filesystems a
ChromiumOS installation has (order of 3-5 iirc?), but indeed it means
your boot will be a bit slower due to it probing more partitions.
Wouldn't expect it to significantly slow down the total boot time
though.
IIRC something more like 12-16, at least for the developer builds I have
used in the past.
I didn't think of this one my WIP is on an Odroid X2 which has a boot
selector jumper, so I have it always starting from mmc0 (which is either
SD or EMMC depending on the jumper setting).
However, it raises an interesting question. The current convention for
Exynos is to first scans external storage (SD, mmc 1) and then internal
storage (eMMC, mmc 0), which opens up a whole different can of worms. As
that means that e.g. my chromebook will try to boot from whatever random
SD i've put into it first rather the OS installed on eMMC. It would be
nice to have some general guidelines in this area so the behaviour of
various boards can be somewhat consistent in the default behaviour.
(Added Ian Cambell to the cc as he introduce the usage on exynos
devices)
The user can select which devices get looked at by setting $boot_targets
to a list of devices names, e.g. "mmc1 mmc0 usb pxe".
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