DRI backwards compatibility problem from X.Org 6.8.0 onwards

[Kevin E Martin]

On Sat, Dec 11, 2004 at 12:52:45AM +0000, Alan Hourihane wrote:
> On Fri, Dec 10, 2004 at 07:04:51PM +0000, Alan Hourihane wrote:
> > Folks,
> > 
> > There's a backwards compatibility breakage with X.Org 6.8.0 and beyond
> > because of revision 1.3 of the file xc/include/glxint.h. So, those
> > that provide binary drivers that were compiled against X.Org 6.7.x or
> > XFree86 4.4.0 or earlier will break as well.
> > 
> > The problem stems from these additional fields in the GLXvisualConfigRec
> > which actually are not needed. 
> > 
> >     int multiSampleSize;
> >     int nMultiSampleBuffers;
> >     int visualSelectGroup;
> 
> Ah,
> 
> It seems as though the DMX code probably added these as it makes use
> of them. 

I just checked and these were added by SGI when they did their glxProxy
work that was included with DMX.  Guy Zadikario <guy at sgi.com> was the
principle author of glxProxy.  I would recommend contacting him to see
if there is another way to implement support for the additional extended
visual properties that would maintain backwards compatibility.  I assume
they were added to support SGI's OpenGL implementation.

One workaround is to surround those fields in GLXvisualConfigRec and the
glxProxy code that uses those fields with #ifdef __sgi/#endif (see patch
attached below).  This would be good to do for 6.8.2 to regain backwards
compatibility.

Alan, do you have a test case that you could use to make sure that I've
not missed anything?

Also, I've created a bugzilla entry for this problem:

    https://bugs.freedesktop.org/show_bug.cgi?id=2070

Thanks,
Kevin
-------------- next part --------------
Index: include/GL/glxint.h
===================================================================
RCS file: /cvs/xorg/xc/include/GL/glxint.h,v
retrieving revision 1.3
diff -u -r1.3 glxint.h
--- include/GL/glxint.h	30 Jun 2004 20:06:52 -0000	1.3
+++ include/GL/glxint.h	13 Dec 2004 02:28:07 -0000
@@ -50,15 +50,21 @@
 				/*    colors are floats scaled to ints */
     int transparentRed, transparentGreen, transparentBlue, transparentAlpha;
     int transparentIndex;
+#ifdef __sgi
     int multiSampleSize;
     int nMultiSampleBuffers;
     int visualSelectGroup;
+#endif
 };
 
 #define __GLX_MIN_CONFIG_PROPS	18
 #define __GLX_MAX_CONFIG_PROPS	500
 
+#ifdef __sgi
 #define __GLX_EXT_CONFIG_PROPS 	10
+#else
+#define __GLX_EXT_CONFIG_PROPS 	7
+#endif
 
 /*
 ** Since we send all non-core visual properties as token, value pairs,
Index: programs/Xserver/hw/dmx/dmx_glxvisuals.c
===================================================================
RCS file: /cvs/xorg/xc/programs/Xserver/hw/dmx/dmx_glxvisuals.c,v
retrieving revision 1.1
diff -u -r1.1 dmx_glxvisuals.c
--- programs/Xserver/hw/dmx/dmx_glxvisuals.c	30 Jun 2004 20:06:53 -0000	1.1
+++ programs/Xserver/hw/dmx/dmx_glxvisuals.c	13 Dec 2004 02:28:08 -0000
@@ -147,12 +147,14 @@
 	    int value = *p++;
 
 	    switch (property) {
+#ifdef __sgi
 	      case GLX_SAMPLES_SGIS:
 		config->multiSampleSize = value;
 		break;
 	      case GLX_SAMPLE_BUFFERS_SGIS:
 		config->nMultiSampleBuffers = value;
 		break;
+#endif
 
 	      case GLX_TRANSPARENT_TYPE_EXT:
 		config->transparentPixel = value;
@@ -177,10 +179,12 @@
 		config->visualRating = value;
 		break;
 
+#ifdef __sgi
 	      /* visualSelectGroup is an internal used property */
 	      case GLX_VISUAL_SELECT_GROUP_SGIX:
 		config->visualSelectGroup = value;
 		break;
+#endif
 
 	      default :
 		/* Ignore properties we don't recognize */
@@ -591,9 +595,11 @@
 	  cfg->transparentBlue = fbcfg->transparentBlue;
 	  cfg->transparentAlpha = fbcfg->transparentAlpha;
 	  cfg->transparentIndex = fbcfg->transparentIndex;
+#ifdef __sgi
 	  cfg->multiSampleSize = fbcfg->multiSampleSize;
 	  cfg->nMultiSampleBuffers = fbcfg->nMultiSampleBuffers;
 	  cfg->visualSelectGroup = fbcfg->visualSelectGroup;
+#endif
        }
     }
 
Index: programs/Xserver/hw/dmx/glxProxy/glxcmds.c
===================================================================
RCS file: /cvs/xorg/xc/programs/Xserver/hw/dmx/glxProxy/glxcmds.c,v
retrieving revision 1.2
diff -u -r1.2 glxcmds.c
--- programs/Xserver/hw/dmx/glxProxy/glxcmds.c	6 Jul 2004 23:51:00 -0000	1.2
+++ programs/Xserver/hw/dmx/glxProxy/glxcmds.c	13 Dec 2004 02:28:08 -0000
@@ -1607,12 +1607,14 @@
 	buf[p++] = pGlxVisual->transparentAlpha;
 	buf[p++] = GLX_TRANSPARENT_INDEX_VALUE_EXT;
 	buf[p++] = pGlxVisual->transparentIndex;
+#ifdef __sgi
 	buf[p++] = GLX_SAMPLES_SGIS;
 	buf[p++] = pGlxVisual->multiSampleSize;
 	buf[p++] = GLX_SAMPLE_BUFFERS_SGIS;
 	buf[p++] = pGlxVisual->nMultiSampleBuffers;
 	buf[p++] = GLX_VISUAL_SELECT_GROUP_SGIX;
 	buf[p++] = pGlxVisual->visualSelectGroup;
+#endif
 
 	WriteToClient(client, __GLX_SIZE_CARD32 * __GLX_TOTAL_CONFIG, 
 		(char *)buf);
Index: programs/Xserver/hw/dmx/glxProxy/glxvisuals.c
===================================================================
RCS file: /cvs/xorg/xc/programs/Xserver/hw/dmx/glxProxy/glxvisuals.c,v
retrieving revision 1.1
diff -u -r1.1 glxvisuals.c
--- programs/Xserver/hw/dmx/glxProxy/glxvisuals.c	30 Jun 2004 20:06:55 -0000	1.1
+++ programs/Xserver/hw/dmx/glxProxy/glxvisuals.c	13 Dec 2004 02:28:09 -0000
@@ -71,10 +71,13 @@
 	   (v1->transparentGreen == v2->transparentGreen) &&
 	   (v1->transparentBlue == v2->transparentBlue) &&
 	   (v1->transparentAlpha == v2->transparentAlpha) &&
-	   (v1->transparentIndex == v2->transparentIndex) &&
-	   (v1->multiSampleSize == v2->multiSampleSize) &&
+	   (v1->transparentIndex == v2->transparentIndex)
+#ifdef __sgi
+	   && (v1->multiSampleSize == v2->multiSampleSize) &&
 	   (v1->nMultiSampleBuffers == v2->nMultiSampleBuffers) &&
-	   (v1->visualSelectGroup == v2->visualSelectGroup)         ) {
+	   (v1->visualSelectGroup == v2->visualSelectGroup)
+#endif
+	  ) {
 
 	      return(1);