Cause: u-boot/Kconfig DISTRO_DEFAULTS missing variables in Kconfig files
u-boot/ config DISTRO_DEFAULTS contains these directives:
select HUSH_PARSER
select BOOTP_BOOTPATH if NET && CMD_NET
select BOOTP_DNS if NET && CMD_NET
select BOOTP_GATEWAY if NET && CMD_NET
select BOOTP_HOSTNAME if NET && CMD_NET
select BOOTP_PXE if NET && CMD_NET
select BOOTP_SUBNETMASK if NET && CMD_NET
select CMDLINE_EDITING
select AUTO_COMPLETE
select SYS_LONGHELP
However net/Kconfig has no references to:
BOOTP_BOOTPATH
BOOTP_DNS
BOOTP_GATEWAY
BOOTP_HOSTNAME
BOOTP_PXE
BOOTP_SUBNETMASK
and possibly common/Kconfig no reference to
HUSH_PARSER
CMDLINE_EDITING
AUTO_COMPLETE
SYS_LONGHELP
Synptom: Causing the lack of option returned on a dhcp request.
Solutions: Three possible solutions to net/Kconfig omissions
1. Add them to Kconfig and select then cmd/Kconfig
2. As they are bootp/dhcp options, always include them ny removing the
preprocessor (ifdef) selections. The code fragments they require are
small, as is the space for the options returned.
3.Configure them when NET and BOOTP or DHCP commands are selected. It
appears they are subordinate to NET features and not stand alone config
options.
I recommend (2). I'm from the simple is good school. This level of
granularity of configuration of the bootp/dchp options appears
unnecessary.
Further action
There needs to be a compile time warning when a select clause in Kconfig
references a directive which does not exist in any included Kconfig
file. Mysteries which require days to find the config variable or days
to resolve are not user friendly.
Any Kconfig define which requires more than a second level
menu option needs close scrutiny. As much as possible a third or
higher level configuration define should be controlled by a
"select" by lower level Kconfig selection.
For documentation there needs to be an autogenerated Kconfig tree,
of the complete tree and with highlighted currently selected
items. An example of this is the systemd "systemctl list
dependencies" command.