[systemd-devel] Excluding .hwdb files

[Kay Sievers]

On Mon, Jul 22, 2013 at 6:18 PM, Michael Biebl <mbiebl at gmail.com> wrote:
> 2013/7/22 Kay Sievers <kay at vrfy.org>:
>> On Mon, Jul 22, 2013 at 3:32 PM, Umut Tezduyar <umut at tezduyar.com> wrote:
>>> For an embedded system that is not using hwdb.bin, we are shipping
>>> roughly 4 mb .hwdb files under /usr/lib/udev/hwdb.d. Is it
>>> distributions responsibility to clean up .hwdb files after build or
>>> should we have a configure option to exclude hwdb support?
>>
>> It's probably not really worth to compile-out the hwdb support, the
>> involved code is quite small.
>>
>> Deleting/sub-packaging the ,hwdb source files (which are only needed
>> to re-compile the database in /etc), or not compiling a the binary
>> database at all should probably be a decision at the packaging/install
>> level, and not a configure option. It should be reasonable easy to do
>> step that at packaging/install time.
>
> Is the data in hwdb really optional, i.e. does it only contain strings
> for representational purposes?

We call it a bit blurry "non-essential" data, means most basic stuff
will work, and the bootup should be successful. It should not contain
data that is needed for integrity of data (no driver quirks that could
cause data loss if missing) or basic device functionality (devices
should show up and be usable, might just miss some additional
features).

But quite a few advanced features might fail in non-obvious ways, like
applying ACls to device nodes for users that log in, scanners, camera
software might not do anything, keyboard multimedia keys are not
mapped, power management might not get active, and a growing number of
things in similar areas. All that stuff that *should* normally work,
but which is not really needed to bring up or debug a machine.

There are no clear rules, it's all new and just how we think of it at
this moment.

Kay