mesa: allow buffers to be mapped multiple times

OpenGL allows a buffer to be mapped only once, but we also map buffers
internally, e.g. in the software primitive restart fallback, for PBOs,
vbo_get_minmax_index, etc. This has always been a problem, but it will
be a bigger problem with persistent buffer mappings, which will prevent
all Mesa functions from mapping buffers for internal purposes.

This adds a driver interface to core Mesa which supports multiple buffer
mappings and allows 2 mappings: one for the GL user and one for Mesa.

Note that Gallium supports an unlimited number of buffer and texture
mappings, so it's not really an issue for Gallium.

v2: fix unmapping in xm_dd.c, remove the GL errors there
v3: fix the intel driver (by Fredrik)

Reviewed-by: Fredrik Höglund <[email protected]>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c b/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c
index a9674ca2db3..49a9bed1921 100644
--- a/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c
+++ b/src/mesa/drivers/dri/i965/intel_pixel_bitmap.c
@@ -79,7 +79,8 @@ static const GLubyte *map_pbo( struct gl_context *ctx,
 
    buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0, unpack->BufferObj->Size,
 						GL_MAP_READ_BIT,
-						unpack->BufferObj);
+						unpack->BufferObj,
+                                                MAP_INTERNAL);
    if (!buf) {
       _mesa_error(ctx, GL_INVALID_OPERATION, "glBitmap(PBO is mapped)");
       return NULL;
@@ -317,7 +318,7 @@ out:
 
    if (_mesa_is_bufferobj(unpack->BufferObj)) {
       /* done with PBO so unmap it now */
-      ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+      ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
    }
 
    intel_check_front_buffer_rendering(brw);