drm/fourcc: fix Amlogic format modifier masks

The comment says the layout and options use 8 bits, and the shift
uses 8 bits. However the mask is 0xf, ie. 0b00001111 (4 bits).

This could be surprising when introducing new layouts or options
that take more than 4 bits, as this would silently drop the high
bits.

Make the masks consistent with the comment and the shift.

Found when writing a drm_info patch [1].

[1]: https://github.com/ascent12/drm_info/pull/67

Signed-off-by: Simon Ser <contact@emersion.fr>
Fixes: d6528ec88309 ("drm/fourcc: Add modifier definitions for describing Amlogic Video Framebuffer Compression")
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210110125103.15447-1-contact@emersion.fr

diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index 723c8e23ca87d1e2ce27a2b006ccb748ae0561d6..5f42a14481bd441f22de1c0e72ef4813a4f0e8c2 100644 (file)
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -1036,9 +1036,9 @@ drm_fourcc_canonicalize_nvidia_format_mod(__u64 modifier)
  * Not all combinations are valid, and different SoCs may support different
  * combinations of layout and options.
  */
-#define __fourcc_mod_amlogic_layout_mask 0xf
+#define __fourcc_mod_amlogic_layout_mask 0xff
 #define __fourcc_mod_amlogic_options_shift 8
-#define __fourcc_mod_amlogic_options_mask 0xf
+#define __fourcc_mod_amlogic_options_mask 0xff
 
 #define DRM_FORMAT_MOD_AMLOGIC_FBC(__layout, __options) \
        fourcc_mod_code(AMLOGIC, \