Re: [Qemu-devel] [PATCHv2 4/8] Store IDE bus id in IDEBus structure for easy access.

[Markus Armbruster]

Gleb Natapov <address@hidden> writes:

> On Fri, Nov 05, 2010 at 05:31:38PM +0100, Markus Armbruster wrote:
>> Gleb Natapov <address@hidden> writes:
>> 
>> > On Fri, Nov 05, 2010 at 03:04:05PM +0100, Markus Armbruster wrote:
>> [...]
>> >> >> >> There has been quite some discussion on "canonical path" on the 
>> >> >> >> list,
>> >> >> >> but no consensus.  Ironically, one of the places where we got stuck 
>> >> >> >> was
>> >> >> >> ISA.  You cut right through that, so that's progress.  Maybe people
>> >> >> >> aren't looking ;)
>> >> >> > That is funny since the problem was already solved looong time ago. 
>> >> >> > Just
>> >> >> > look at Open Firmware device path. They are capable of addressing all
>> >> >> > devices just fine, ISA devices included. What specific problem you 
>> >> >> > had
>> >> >> > with ISA bus? 
>> >> >> 
>> >> >> Lack of consensus.  I was in favour of using I/O base, just like you 
>> >> >> do.
>> >> >> There were worries about ISA devices not using any I/O ports.
>> >> > There is a solution for that problem for almost 15 years and we are
>> >> > still looking for consensus on qemu list?! Here is ISA device binding
>> >> > spec for Open Firmware: 
>> >> > http://playground.sun.com/1275/bindings/isa/isa0_4d.ps 
>> >> > If ISA device have no IO ports MMIO is used.
>> >> 
>> >> Precedence should promote consensus, but it can't replace it.  If you
>> >> can push the list to consensus, more power to you.
>> > I do not see disagreement right now :) You are saying you agree. Blue
>> > Swirl asked me to use Open Firmware so I assume he agrees to. So who is
>> > against and what are his arguments?
>> 
>> Start here:
>> 
>> http://lists.nongnu.org/archive/html/qemu-devel/2010-06/msg01618.html
>
> I saw this in fact. The wouldn't agree with this device path proposal
> too. It mixes qemu internal names (which is a big no-no for my purpose)
> and bus addresses. Paul made sensible points there and if you look
> closely what he proposes is what I implemented here. Regarding ISA
> ("busses that don't have a consistent addressing scheme" he called it)
> he himself proposed to use address of the first IO port/memory region
> as an ID. This is what is already implemented by my patch.

You don't have to convince me; I was with Paul in that thread.

Regarding DeviceInfo member name values being QEMU internal: hardly.
They're ABI.  They're what we use to identify device types on external
interfaces including command line, human monitor and QMP.