gbm: Export a get modifiers

This patch originally had i965 specific code and was named:
commit 61cd3c52b868cf8cb90b06e53a382a921eb42754
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Thu Oct 20 18:21:24 2016 -0700

    gbm: Get modifiers from DRI

To accomplish this, two new query tokens are added to the extension:
__DRI_IMAGE_ATTRIB_MODIFIER_UPPER
__DRI_IMAGE_ATTRIB_MODIFIER_LOWER

The query extension only supported 32b queries, and modifiers are 64b,
so we needed two of them.

NOTE: The extension version is still set to 13, so none of this will
actually be called.

v2: Error handling of queryImage (Emil)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

src/gbm/backends/dri/gbm_dri.c

@@ -39,6 +39,7 @@
 #include <unistd.h>
 #include <dlfcn.h>
 #include <xf86drm.h>
+#include <drm_fourcc.h>
 
 #include <GL/gl.h> /* dri_interface needs GL types */
 #include <GL/internal/dri_interface.h>
@@ -53,6 +54,14 @@
 #include "../../../egl/wayland/wayland-drm/wayland-drm.h"
 #endif
 
+#ifndef DRM_FORMAT_MOD_INVALID
+#define DRM_FORMAT_MOD_INVALID ((1ULL<<56) - 1)
+#endif
+
+#ifndef DRM_FORMAT_MOD_LINEAR
+#define DRM_FORMAT_MOD_LINEAR 0
+#endif
+
 static __DRIimage *
 dri_lookup_egl_image(__DRIscreen *screen, void *image, void *data)
 {
@@ -735,6 +744,38 @@ gbm_dri_bo_get_offset(struct gbm_bo *_bo, int plane)
    return (uint32_t)offset;
 }
 
+static uint64_t
+gbm_dri_bo_get_modifier(struct gbm_bo *_bo)
+{
+   struct gbm_dri_device *dri = gbm_dri_device(_bo->gbm);
+   struct gbm_dri_bo *bo = gbm_dri_bo(_bo);
+
+   if (!dri->image || dri->image->base.version < 14) {
+      errno = ENOSYS;
+      return DRM_FORMAT_MOD_INVALID;
+   }
+
+   /* Dumb buffers have no modifiers */
+   if (!bo->image)
+      return DRM_FORMAT_MOD_LINEAR;
+
+   uint64_t ret = 0;
+   int mod;
+   if (!dri->image->queryImage(bo->image, __DRI_IMAGE_ATTRIB_MODIFIER_UPPER,
+                               &mod))
+      return DRM_FORMAT_MOD_INVALID;
+
+   ret = (uint64_t)mod << 32;
+
+   if (!dri->image->queryImage(bo->image, __DRI_IMAGE_ATTRIB_MODIFIER_LOWER,
+                               &mod))
+      return DRM_FORMAT_MOD_INVALID;
+
+   ret |= mod;
+
+   return ret;
+}
+
 static void
 gbm_dri_bo_destroy(struct gbm_bo *_bo)
 {
@@ -1278,6 +1319,7 @@ dri_device_create(int fd)
    dri->base.base.bo_get_handle = gbm_dri_bo_get_handle_for_plane;
    dri->base.base.bo_get_stride = gbm_dri_bo_get_stride;
    dri->base.base.bo_get_offset = gbm_dri_bo_get_offset;
+   dri->base.base.bo_get_modifier = gbm_dri_bo_get_modifier;
    dri->base.base.bo_destroy = gbm_dri_bo_destroy;
    dri->base.base.destroy = dri_destroy;
    dri->base.base.surface_create = gbm_dri_surface_create;

src/gbm/gbm-symbols-check

@@ -23,6 +23,7 @@ gbm_bo_get_handle
 gbm_bo_get_fd
 gbm_bo_get_plane_count
 gbm_bo_get_handle_for_plane
+gbm_bo_get_modifier
 gbm_bo_write
 gbm_bo_set_user_data
 gbm_bo_get_user_data

src/gbm/main/gbm.c

@@ -280,6 +280,25 @@ gbm_bo_get_handle_for_plane(struct gbm_bo *bo, int plane)
    return bo->gbm->bo_get_handle(bo, plane);
 }
 
+/**
+ * Get the chosen modifier for the buffer object
+ *
+ * This function returns the modifier that was chosen for the object. These
+ * properties may be generic, or platform/implementation dependent.
+ *
+ * \param bo The buffer object
+ * \return Returns the selected modifier (chosen by the implementation) for the
+ * BO.
+ * \sa gbm_bo_create_with_modifiers() where possible modifiers are set
+ * \sa gbm_surface_create_with_modifiers() where possible modifiers are set
+ * \sa define DRM_FORMAT_MOD_* in drm_fourcc.h for possible modifiers
+ */
+GBM_EXPORT uint64_t
+gbm_bo_get_modifier(struct gbm_bo *bo)
+{
+   return bo->gbm->bo_get_modifier(bo);
+}
+
 /** Write data into the buffer object
  *
  * If the buffer object was created with the GBM_BO_USE_WRITE flag,

src/gbm/main/gbm.h

@@ -327,6 +327,9 @@ gbm_bo_get_handle(struct gbm_bo *bo);
 int
 gbm_bo_get_fd(struct gbm_bo *bo);
 
+uint64_t
+gbm_bo_get_modifier(struct gbm_bo *bo);
+
 int
 gbm_bo_get_plane_count(struct gbm_bo *bo);
 

src/gbm/main/gbmint.h

@@ -82,6 +82,7 @@ struct gbm_device {
    union gbm_bo_handle (*bo_get_handle)(struct gbm_bo *bo, int plane);
    uint32_t (*bo_get_stride)(struct gbm_bo *bo, int plane);
    int64_t (*bo_get_offset)(struct gbm_bo *bo, int plane);
+   uint64_t (*bo_get_modifier)(struct gbm_bo *bo);
    void (*bo_destroy)(struct gbm_bo *bo);
 
    struct gbm_surface *(*surface_create)(struct gbm_device *gbm,