Re: [XenPPC] [pushed] [ppc] serial port discovery and zilog device driver

[Hollis Blanchard <hollisb@xxxxxxxxxx>]

On Fri, 2006-05-26 at 13:13 -0400, Maria Butrico wrote:
> 
> I re-read the email and I think I adopted your suggestions.  Some are
> in 
> the last patch I sent and some in the one that was committed.  What I 
> did not do is to invoke the serial port initialization code from the 
> platform specific initialization.

Ignore the specific "platform" vs "serial port" detection for a moment.
It is the same scenario: you have a property, and from that value you
need to decide what code to call. Your approach (in both cases) was to
define a global structure and an enum. My counter-proposal is explained
at
http://lists.xensource.com/archives/html/xen-ppc-devel/2006-04/msg00042.html . 
Despite that, you continued to use the global structure/enum approach in the 
patch which was just committed.

> I think a broader discussion is 
> merited on this, and the other issue you raised elsewhere regarding 
> simple vs canonical probes.  I do not think it is useful to hold this 
> discussion as a consequence of a patch. 

That is the best time to have the discussion. Actually, the best time is
*before* the patch is committed, but that's an issue for Jimi. I'm
strongly tempted to revert the patch in question, not because I don't
like you, but because there is obviously some disagreement over it, so
it's clear it was committed prematurely.

> Between the serial port detection and the platform detection patch
> there was a change, that is, we thought we could delay the platform
> detection and do it against the OFD tree.  In retrospect, that would
> have been too late.  Since we now do the platform detection earlier
> (from boot_of.c), then we could probably switch the serial port
> initialization there too.

Yes, it looks like we can call ns16550_init() quite early.

>   Unfortunately the detection of the serial port and the
> identification of its address does not change much one way or another.

Is this a problem? If so I don't understand the issue.

> Beside Jimi, Hollis and myself, who else is interested in this issue
> and wants to participate in a meeting to discuss this? 

I didn't realize there was still confusion. Maybe we can try to clear it
up by email first?

-- 
Hollis Blanchard
IBM Linux Technology Center


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