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 <fredrik@kde.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/src/mesa/drivers/dri/i965/intel_buffer_objects.h b/src/mesa/drivers/dri/i965/intel_buffer_objects.h
index 3b6d835..2197707 100644
--- a/src/mesa/drivers/dri/i965/intel_buffer_objects.h
+++ b/src/mesa/drivers/dri/i965/intel_buffer_objects.h
@@ -42,9 +42,8 @@ struct intel_buffer_object
    struct gl_buffer_object Base;
    drm_intel_bo *buffer;     /* the low-level buffer manager's buffer handle */
 
-   drm_intel_bo *range_map_bo;
-   void *range_map_buffer;
-   unsigned int range_map_offset;
+   drm_intel_bo *range_map_bo[MAP_COUNT];
+   void *range_map_buffer[MAP_COUNT];
 
    /** @{
     * Tracking for what range of the BO may currently be in use by the GPU.