[meta-ti] [PATCH 0/4] IMAGE_FSTYPES fixes / improvements

[Koen Kooi]

Op 8 mrt. 2012, om 22:01 heeft Denys Dmytriyenko het volgende geschreven:

> On Thu, Mar 08, 2012 at 12:34:00PM -0700, Tom Rini wrote:
>> Hey all,
>> 
>> This short series does two things.  For 3 machines we fix a bug of using
>> '?=' rather than '+=' for setting IMAGE_FSTYPES (these are all of the
>> machines that have this issue today except for...) and on the 4th,
>> am335x-evm we add UBI support as well.  On the first three, these are
>> correct by inspection and on the fourth, I've written to and mounted
>> systemd-image from NAND on my EVM (it didn't work as I was using a custom
>> uImage that's not systemd-sane, and fixing that and confirming the config
>> used here works is on my list).
> 
> All,
> 
> Tom and I started talking on IRC and then decided to move the discussion back 
> to the mailing list for others to participate.
> 
> So, basically, the proposal is to do this in our machine.conf files:
> 
> -IMAGE_FSTYPES ?= "jffs2 tar.bz2"
> +IMAGE_FSTYPES += "jffs2 tar.bz2"
> 
> My response was that we shouldn't do that.

+= is the OE classic way of doing things and is IMNSHO the right thing.

> The conf files that may set, append 
> or overwrite IMAGE_FSTYPES are parsed in the order of local.conf, machine.conf 
> and distro.conf. And if none of those set IMAGE_FSTYPES, bitbake.conf defaults 
> to a sane tar.gz. From end-user perspective, they expect the setting in their 
> local.conf to be obeyed. If they don't care and don't set IMAGE_FSTYPES, then 
> machine.conf will set it to supported values, i.e. jffs2 and tar.bz2 in our 
> case. Of course, distro has the last word and potentially can alter it, but in 
> most cases it shouldn't. That's how it works now and I believe it's the 
> correct behaviour. Changing it to append additional values to what user wants 
> is slightly heavy-handed, in my opinion. In other words, those are suggested 
> image types, not enforced ones.
> 
> As Tom poined out, this is the same behaviour as currently used in OE-Core, 
> where qemu machines all have IMAGE_FSTYPES ?= "tar.bz2 ext3".
> 
> The original issue in question may be coming from the way some setup scripts 
> pre-configure user settings in local.conf, defaulting IMAGE_FSTYPES to 
> something, that is not very suitable for the machines being used. This needs 
> to be left unset and for the end-user to decide and set specifically, IMHO.
> 
> Comments, opinions?

See the discussion on OE-core a while back. There was a lot of handwaving done and suggested that IMAGE_FSTYPES_append_$machine = " foo" in local.conf is the right way to do this. I think it's not intuitive because you have to remember that += and _append are expanded in different points during parsing, which requires either deep bitbake knowledge or minor braindamage.

regards,

Koen