[yocto] packagegroup-core-boot failure for RTC-less system

[Paul Eggleton]

On Monday 10 December 2012 18:58:14 Jon Szymaniak wrote:
> I have a MACHINE_FEATURES which *does not* include "rtc", as the platform I
> am working on doesn't have an RTC.
> 
> The busybox bbappend I'm using (attached below) uses the provided
> defconfig, but
> disables the HWCLOCK features.
> 
> However, my build is failing due to packagegroup-core-boot being unable to
> meet the busybox-hwclock dependency. Looking at this line from
> packagegroup-core-boot.bb, it seems to me that busybox-hwlock shouldn't be
> getting placed in the core-boot's RDEPENDS, given that my MACHINE_FEATURES
> does not include "rtc":
> 
>     ${@base_contains("MACHINE_FEATURES", "rtc", "busybox-hwclock", "", d)} \
> 
> 
> Any thoughts or tips on debugging this? Perhaps there's somewhere I can
> stick a print of MACHINE_FEATURES to verify that it is what I thought I
> set?

The way to query the final value of MACHINE_FEATURES is:

bitbake -e | grep ^MACHINE_FEATURES=

FYI though, rtc is a "backfilled" feature - because it was introduced later on 
and we didn't want to break existing machines that do have an RTC and don't 
yet have "rtc" in MACHINE_FEATURES, we added it to MACHINE_FEATURES_BACKFILL. 
In order to prevent it from being backfilled, you can add the following to your 
machine config:

MACHINE_FEATURES_BACKFILL_CONSIDERED = "rtc"

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre