glamor: Add documentation of the usage hints.modesetting-gbm

Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/glamor/glamor.h b/glamor/glamor.h
index 8616fadb0..7875df8aa 100644
--- a/glamor/glamor.h
+++ b/glamor/glamor.h
@@ -137,9 +137,28 @@ extern _X_EXPORT PixmapPtr glamor_create_pixmap(ScreenPtr screen, int w, int h,
                                                 int depth, unsigned int usage);
 extern _X_EXPORT Bool glamor_destroy_pixmap(PixmapPtr pixmap);
 
+/**
+ * Creates a pixmap with no glamor private, and just CPU-side pixels
+ * managed by fb.
+ */
 #define GLAMOR_CREATE_PIXMAP_CPU        0x100
+/**
+ * Creates a pixmap with no GL FBO attached, to slightly optimize
+ * cases where we know only texturing will be done to it.
+ */
 #define GLAMOR_CREATE_FBO_NO_FBO        0x103
+/**
+ * Creates a pixmap that is definitely not large-texture tiled mode.
+ *
+ * If the size is too large to not be tiled, the pixmap allocation
+ * will fail.
+ */
 #define GLAMOR_CREATE_NO_LARGE          0x105
+/**
+ * Creates a pixmap with a glamor private but no backing storage yet.
+ * Can be used if you're going to attach backing storage later, like
+ * in a DRI3 pixmap-from-BO hook.
+ */
 #define GLAMOR_CREATE_PIXMAP_NO_TEXTURE 0x106
 
 /* @glamor_egl_exchange_buffers: Exchange the underlying buffers(KHR image,fbo).