1 files changed, 8 insertions, 7 deletions

diff --git a/src/mesa/drivers/dri/sis/sis_state.c b/src/mesa/drivers/dri/sis/sis_state.c
index 305c63f73f..cb672c2c7c 100644
--- a/src/mesa/drivers/dri/sis/sis_state.c
+++ b/src/mesa/drivers/dri/sis/sis_state.c
@@ -546,23 +546,24 @@ void sisDDDrawBuffer( GLcontext *ctx, GLenum mode )
    __GLSiSHardware *prev = &smesa->prev;
    __GLSiSHardware *current = &smesa->current;
 
-   /*
-    * _DrawDestMask is easier to cope with than <mode>.
-    */
+   if (ctx->DrawBuffer->_NumColorDrawBuffers != 1) {
+      FALLBACK( smesa, SIS_FALLBACK_DRAW_BUFFER, GL_TRUE );
+      return;
+   }
+
    current->hwDstSet &= ~MASK_DstBufferPitch;
-   switch ( ctx->DrawBuffer->_ColorDrawBufferMask[0] ) {
-   case BUFFER_BIT_FRONT_LEFT:
+   switch ( ctx->DrawBuffer->_ColorDrawBufferIndexes[0] ) {
+   case BUFFER_FRONT_LEFT:
       FALLBACK( smesa, SIS_FALLBACK_DRAW_BUFFER, GL_FALSE );
       current->hwOffsetDest = smesa->front.offset >> 1;
       current->hwDstSet |= smesa->front.pitch >> 2;
       break;
-   case BUFFER_BIT_BACK_LEFT:
+   case BUFFER_BACK_LEFT:
       FALLBACK( smesa, SIS_FALLBACK_DRAW_BUFFER, GL_FALSE );
       current->hwOffsetDest = smesa->back.offset >> 1;
       current->hwDstSet |= smesa->back.pitch >> 2;
       break;
    default:
-      /* GL_NONE or GL_FRONT_AND_BACK or stereo left&right, etc */
       FALLBACK( smesa, SIS_FALLBACK_DRAW_BUFFER, GL_TRUE );
       return;
    }