Why is sbc a 32bit field in xGLXBufferSwapComplete2 and
xDRI2BufferSwapComplete2 when it is a 64bit field in GLXBufferSwapComplete?
The hunk at the bottom will result in casting a 64bit int to a 32bit int. If
you're going to change this, shouldn't you also change GLXBufferSwapComplete,
DRI2SwapEvent() and everything else that has a 64bit swap count?
Isn't it easier to correct the spec to match reality?
--- a/hw/xfree86/dri2/dri2ext.c
+++ b/hw/xfree86/dri2/dri2ext.c
@@ -359,7 +359,7 @@ static void
DRI2SwapEvent(ClientPtr client, void *data, int type, CARD64 ust, CARD64 msc,
CARD64 sbc)
{
- xDRI2BufferSwapComplete event;
+ xDRI2BufferSwapComplete2 event;
DrawablePtr pDrawable = data;
event.type = DRI2EventBase + DRI2_BufferSwapComplete;
@@ -369,8 +369,7 @@ DRI2SwapEvent(ClientPtr client, void *data, int type,
CARD64 ust, CARD64 msc,
event.ust_lo = ust & 0xffffffff;
event.msc_hi = (CARD64)msc >> 32;
event.msc_lo = msc & 0xffffffff;
- event.sbc_hi = (CARD64)sbc >> 32;
- event.sbc_lo = sbc & 0xffffffff;
+ event.sbc = sbc;
WriteEventsToClient(client, 1, (xEvent *)&event);
}
On May 5, 2011, at 08:28, Jesse Barnes wrote:
> On Wed, 4 May 2011 21:29:23 -0700
> Jeremy Huddleston <jerem...@freedesktop.org> wrote:
>
>> Yeah... so considering the comments in mesa-dev earlier today, I was really
>> surprised to see that glproto and dri2proto were tagged today. I think we
>> need to brownbag retract and rethink this.
>
> Damnit; right when Dave mentioned this last night I knew I had gone too
> far in trying to make sure the fix was propagated. I hate it when he's
> right!
>
> Yeah, having a rule that we can't touch existing proto structs makes
> sense unless we want to do a major break. It certainly makes pushing
> out updates eaiser and preserves bisection...
>
>> These changes break API. I'm all for fixing the structs, but anything that
>> breaks API (or worse, protocol) certainly warrants much more than the +0.0.1
>> version bump. This also makes it impossible to build the current dev and
>> current stable with the same protos installed. I haven't looked at the
>> details specifically, but I suspect that it also changes what is on the
>> wire, meaning clients and the server may disagree depending on which glproto
>> version they were using. Is that the case? If not, can't we solve this
>> with some creative union{}ing?
>
> In this case, what's on the wire is pretty much the same; if the client
> and server don't match, you may get a different kind of corruption in
> the affected field (0 vs some other value), but things are no worse.
>
>> Either way, I think we should retract the glproto 1.4.13 release until we
>> can get this straightened out.
>
> Ok; fwiw my rationale was twofold:
> 1) make sure master requires the new proto headers to avoid some of
> the trouble we've had in the past with ifdefs and untested paths
> (though again, the failure mode is benign in this case)
> 2) make the proto breakage obvious even for older code; the fix is
> trivial
>
> But I guess (2) is a bit much... after pushing I started having
> nightmares about the input proto changes from awhile back.
>
> Here are what the backwards compatible changes look like... Look
> better?
>
> Thanks,
> --
> Jesse "Breaker of Builds" Barnes
> <dri2proto-compat-fix.patch><glproto-compat-fix.patch><mesa-glx-compat-fix.patch><xserver-glproto-compat-fix.patch>
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