[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#741190: qt4-x11: Improve atomic support on parisc



On Friday 04 April 2014 11:46:23 John David Anglin wrote:
> On 4/3/2014 10:19 PM, Lisandro Damián Nicanor Pérez Meyer wrote:
> > OK, here's what upstream replied wrt the patch:
> >    Sorry, there's no way we can accept this patch. It is totally binary-
> >    incompatible for PA-RISC since it changes the size of QAtomicInt.
> >    Debian will need to keep the patch and ensure that everything is built
> >    with
> >    the patch applied (or without it).
> 
> As noted in message #25, I was worried about this.  However, this is an
> essential part of
> the change and I don't see any other way to resolve bug #708200.  If you
> have any suggestions
> for resolving it without changing qt4-x11, let me know.

I'm ok on breaking binary compatibility just in Debian just for parisc because 
it's not a release arch. Would it have been otherwise, then not.
 
> >    What's more, I m not sure that you can set the IS_WAIT_FREE macros,
> >    since
> >    they are probably not wait-free. Just because you removed the explicit
> >    lock
> >    doesn't mean GCC won't use one behind your back in the __sync
> >    functions. I
> >    know it does that for ARM for types whose size are not 4 bytes. And
> >    knowing
> >    PA-RISC doesn't have wait-free atomic instructions, I doubt GCC can do
> >    it
> >    wait free either.
> > 
> > I will not have any problem to keep this delta **if and only if** you can
> > prove is safe to set IS_WAIT_FREE macros.
> 
> Based on this page <http://qt-project.org/doc/qt-5/QAtomicInt.html>, the
> macro defines need
> to stay as they were before.  The implementation is not lock or loop
> free.  I will update the patch
> and retest.

Cool :)


-- 

Lisandro Damián Nicanor Pérez Meyer
http://perezmeyer.com.ar/
http://perezmeyer.blogspot.com/

Attachment: signature.asc
Description: This is a digitally signed message part.


Reply to: