[PATCH] dix: Fill in errorValue in ChangeGC for tile/stipple/clip BadMatch

[Peter Hutterer]

On Mon, Jun 20, 2011 at 06:50:47PM -0400, Adam Jackson wrote:
> On 6/20/11 6:18 PM, Peter Hutterer wrote:
> >On Sat, Jun 18, 2011 at 09:25:48AM +0200, Keith Packard wrote:
> >>On Fri, 17 Jun 2011 15:26:41 -0400, Adam Jackson<ajax at redhat.com>  wrote:
> >>
> >>>+		    if (client)
> >>>+			client->errorValue = pPixmap->drawable.id;
> >>>  		    error = BadMatch;
> >>
> >>Oddly enough, a Match error does not return the mis-matching value.
> >
> >why not? can we change it? why not start doing so?
> 
> The protocol spec simply says "Other core errors return no
> additional data", where other happens to include BadMatch.
> 
> The caveat here is that unused data in errors isn't guaranteed to be
> 0, which means you'd have to know to only look for extra BadMatch
> info for either a particular server version or (better) protocol
> version.  You could reasonably make that part of protocol 11.1, on
> the assumption that 11.0 clients wouldn't bother looking for it, but
> that 11.1 clients would want to be assured of it.

seems like a fairly simple (if possibly large) change to the server that
would be an ideal testbed for bumping the protocol minor to see how many
clients can't cope with it. If it goes well, we should be able to bump the
core protocol for other useful stuff in the future.

Cheers,
  Peter