Thread (673 messages) flat view 673 messages, 6 authors, 2021-03-05
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[PATCH 5.10 158/663] drm/fourcc: fix Amlogic format modifier masks

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-03-01 23:14:00
Also in: lkml
Subsystem: drm drivers, drm drivers and misc gpu patches, the rest · Maintainers: David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds

From: Simon Ser <redacted>

[ Upstream commit cc3283f8f41f741fbaef63d0503d8fb4a7919100 ]

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 <redacted>
Fixes: d6528ec88309 ("drm/fourcc: Add modifier definitions for describing Amlogic Video Framebuffer Compression")
Cc: Neil Armstrong <redacted>
Cc: Sam Ravnborg <redacted>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Daniel Vetter <redacted>
Acked-by: Neil Armstrong <redacted>
Link: https://patchwork.freedesktop.org/patch/msgid/20210110125103.15447-1-contact@emersion.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/uapi/drm/drm_fourcc.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index 82f3278012677..5498d7a6556a7 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -997,9 +997,9 @@ 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, \
-- 
2.27.0


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