Hi Heinrich,
On Sun, 26 Apr 2020 at 18:58, Heinrich Schuchardt xypron.glpk@gmx.de wrote:
Am April 27, 2020 12:29:29 AM UTC schrieb Simon Glass sjg@chromium.org:
At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This is wasteful when the system already has a suitable version available.
Update the Makefile logic to build dtc only if the version available is too old.
This saves about 2.5 seconds of elapsed time on a clean build for me.
- Add a patch to bring back the dtc-version.sh script
- Update the check to make sure libfdt is available if needed
U -Boot has been set up to create reproducible builds. With this patch dtc will have to be made a build dependency to provide reproducibility. Cf. https://www.debian.org/doc/debian-policy/ch-source.html#reproducibility
This may require changes in the packaging of U-Boot in Linux distributions. Nothing to stop this patch, just something to keep in mind.
You presume that future versions of dtc will always be backward compatible with U-Boot. Ok, we do the same for other tools like gcc too (with surprises at each new major release).
Cc: Vagrant
Should we disable this check (and always build dtc) when doing a repeatable build? Is that SOURCE_DATE_EPOCH?
Regards, SImon
Regards, Simon