configurable device (and other) tables in the kernel ?

[M. Warner Losh]

In message: <20070203043250.A8294 at xorpc.icir.org>
            Luigi Rizzo <rizzo at icir.org> writes:
: On Sat, Feb 03, 2007 at 11:55:03AM +0000, Robert Watson wrote:
: ...
: > The preferred way to make configuration frobs available during early boot is 
: > via the hints mechanism, which supports both loading data via the loader, 
: > compiling it into the kernel, and updating it using kenv(8).  I'd really like 
: > us avoid adding yet more file access dependencies in the kernel.  These tend 
: > to be fragile, can only run in certain contexts, run into issues with changing 
: > roots, etc.  Could we add /boot/deviceids.hints to match /boot/device.hints?
: 
: ok i was just asking for what the available options are.
: 
: But in another private email i was mentioning that the bootloader
: "load" mechanism also already support loading opaque files
: and seems to pass the info to the kernel (preloaded_files ?),
: and this would overcome what i think is a limitation of the hints/kenv
: mechanism (more below).
: 
: Following your principle (which i agree with) there would be no reason to
: have a separate the firmware(9) mechanism except that:
: 
: + the hints/kenv/loader variables/resource mechanism has too many
:   different names so people get confused on what it really is or can do;
: 
: + documentation is also lacking a lot. E.g. "man -k hints" does not
:   mention kenv(2), which in turn does not mention any of the
:   resource_*(9) calls ("man -k resource" lists a few but not all
:   of them, but you have to know in the first place that 'resource'
:   and 'hint' are related, see previous point).
: 
: + it seems to me that hints are only good at storing C strings i.e.
:   single lines of plain text. There is no support for opaque binary
:   data files.
: 
: + the internal organization of hints is just a single list. Even if
:   one forgets about binary data and tries to store some large tables
:   (device ids, quirks etc) as multiple one-line name=value entries,
:   the mechanism doesn't scale.
: 
: All of the above can be fixed - especially the documentation part,
: but that doesn't mean that the hints mechanism can already do
: what i was asking; there is still a bit of work to do...

True.  Things could be better documented.

However, the more fundamental problems remain.  It does no good to
have a fancy binary loader with every kind of plug and play info if
few of the drivers in the system use tables in a consistant way.
That's a big problem to solve...

Warner