Stop supporting direct partitioning of MMC

[Loïc Minier]

Hi

In bug #717129, we came to the conclusion that linaro-media-create would be much more robust if it systematically generated an image file and optionally wrote that to a real SD card instead of trying to partition SD cards on the fly; the latter causes some bad effects with some systems with certain USB readers and certain SD cards.

This would also allow simplifying the sfdisk_cmd code for root partition a bit.

One issue is how to resize the rootfs to the right size to fill the SD card. We could do this on boot on the target with packages like cloud-initramfs-growroot for instance.

Cheers,

[Mattias Backman (mabac)]

Loïc and Guilherme discussed this on irc last week, I'll try to summarize.

This change can be implemented as creating an image with a roughly calculated size, write it to SD and then resize to fit the card using parted. The proposed size for the initial image is
   (gzip -l on rootfs) + (100 MB per hwpack) + (some free space e.g. 200 MB)

[Mattias Backman (mabac)]

The proposed change would not easily allow for reusing parts of an existing card (now known as "merge mode") and the question was raised whether it is really needed.

I think the discussion ended with a user survey being a good idea, but no concrete plan for such a survey.

[Loïc Minier (lool)]

This hits a lot of users and that's the only way we found to deal with writing directly to MMCs

NB: I think merge mode isn't a concern anymore

[Loïc Minier (lool)]

See also bug #866043

[Alan Bennett (akbennett)]

Due to the age of this issue, we are acknowledging that this issue will likely not be fixed, is no longer applicable, or was already fixed by an indirect change. If this issue is still important, please add details and reopen the issue.