[Bug 1001614] eCos GDB stub "detach" reply confusing with GDB 7.4.1

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--- Comment #6 from Jonathan Larmour <jifl@ecoscentric.com> 2012-07-01 00:08:55 BST ---
Created an attachment (id=1810)
 --> (http://bugs.ecos.sourceware.org/attachment.cgi?id=1810)
Patch to remove 'detach' support

(In reply to comment #5)
> 
> Someone, way back, decided that the eCos GDB stub should do _something_ with
> detach requests rather than nothing at all.

As I mentioned before, my assumption for the rationale has been that it was
thought better to return to a ROM monitor (which, given Mark made this change,
would have been in the context of CygMon!) than just remain stuck in the stub.
As I said before this rationale is arguable. That doesn't make it right.

> The processing of 'D' packets was
> explicitly added to the stub 2001-08-24. It does seem strange to me that we
> currently issue an empty reply (indicating that the command is not supported)
> but then we go ahead and do something anyway (albeit with modified semantics).
> 
> I agree that it would be preferable to implement correct detach semantics. I
> also agree that this not necessarily high priority. In the meantime, replying
> "OK" ("I'm going to do something") still seems more correct to me than replying
> with an empty string ("I'm ignoring this").

But OK doesn't mean "I'm going to do something", it means "I'm going to
detach". But it doesn't do that.

So again, can you clarify what purpose you have for wanting to use detach,
since given the patch, you would want it to be doing something which is more
accurately served by 'kill'.

There are other GDB features that can't be properly supported by eCos, such as
inferior function calling - we don't promise to support everything GDB provides
just because GDB provides it.

So personally, I would be equally happy to remove 'D' packet support as
implement detach support. All that's needed is the attached patch. If no-one
needs detach semantics, then we should remove it as it doesn't match the
documented behaviour. Then GDB will return "Remote doesn't know how to detach"
and everything will be consistent with documented behaviour.

But it depends on why you wanted to use detach in the first place.

Jifl

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