Re: [RFC] Design changes for bidirectional interface compatibility.

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 24/08/2022 16:31, Martin Harvey wrote:
> I have a request for comments on some design changes which would 
> considerably ease our support load, and work towards solving VM upgrade 
> issues with PV drivers installed. Since it was originally a wiki, I’ve 
> had to convert it to PDF, which I hope is a format that most readers of 
> this list find acceptable.
> Design doc v1 in PDF format:
>
> https://citrix.sharefile.com/d-s722cae4e280f4148ae689f972a2cea10 
> <https://citrix.sharefile.com/d-s722cae4e280f4148ae689f972a2cea10>
> Paul, there is further documentation concerning details of shortcomings 
> of the current system which I shall send to you separately.
Can you send it to the list too? I don't see a problem statement in your 
doc. What precisely is the problem with the current mechanism? The 
currently implemented use of PDO names to match available interface 
versions was very deliberately chosen to avoid the need for any child 
driver to maintain compatibility with an older parent. As long as the 
rule is followed (i.e a new interface combo in the parent requires that 
the PDO rev is bumped) there really should not be any compatibility 
problem to fix.
  Paul