On Thu, 05 May 2011 13:36:40 -0700
Jeremy Huddleston <jerem...@apple.com> wrote:

> >> Yes, I realize that there are some areas that use 64bit for sbc.  Do we 
> >> really need 64bits for this?  If so, how do we properly to communicate the 
> >> 64bit value between server/client?  Currently, your changes result in an 
> >> implicit cast from 64bit to 32bits in DRI2SwapComplete which will cause 
> >> problems if we really do need those extra bits:
> >> 
> >>    if (swap_complete)
> >>        swap_complete(client, swap_data, type, ust, frame, 
> >> pPriv->swap_count);
> >> 
> >> It looks to me like much more of DRI2 should be rewritten to use 32bit 
> >> swap counts, or there should be some other mechanism in place to 
> >> communicate the full 64bit value.
> > 
> > Yeah there are other mechanisms (the OML sync extension) for
> > communicating the whole 64 bits.  Both the swap reply and msc reply
> > deal in the full 64 bits, just the swap event (an unrelated extension)
> > truncates to 32 bits.  (Also I think the 64 bit size for swap count in
> > the OML extension is just inertia; getting to a count that high even at
> > 120Hz is going to take awhile.)
> 
> Ok, well this all really doesn't sit well with me, but it would put my mind 
> slightly at ease if you would do some logging of the problem if we encounter 
> it in DRI2SwapComplete.  That might give your future self some clue as to 
> what is going wrong when you see issues down the road:
> 
>    if (swap_complete) {
>        if (pPriv->swap_count > 0xffffffff)
>            ErrorF("something appropriate");
>        swap_complete(client, swap_data, type, ust, frame, 
> (CARD32)pPriv->swap_count);
>    }

Yeah, it's annoying.  How about I leave out the error message and handle
wrapping on the client side instead?  That way at least the client code
won't notice that the server is only transmitting 32 bits...

-- 
Jesse Barnes, Intel Open Source Technology Center
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