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From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Russell King <linux@armlinux.org.uk>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH resend] drm/armada: Fix off-by-one error in armada_overlay_get_property()
Date: Mon, 21 Nov 2022 16:43:14 +0100	[thread overview]
Message-ID: <788e97ac9b2aeee1941f274bf7b279b68c7592b6.1669045360.git.geert+renesas@glider.be> (raw)

As ffs() returns one more than the index of the first bit set (zero
means no bits set), the color key mode value is shifted one position too
much.

Fix this by using FIELD_GET() instead.

Fixes: c96103b6c49ff9a8 ("drm/armada: move colorkey properties into overlay plane state")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Compile-tested only.
---
 drivers/gpu/drm/armada/armada_overlay.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/armada/armada_overlay.c b/drivers/gpu/drm/armada/armada_overlay.c
index f21eb8fb76d87285..3b9bd8ecda137f6d 100644
--- a/drivers/gpu/drm/armada/armada_overlay.c
+++ b/drivers/gpu/drm/armada/armada_overlay.c
@@ -4,6 +4,8 @@
  *  Rewritten from the dovefb driver, and Armada510 manuals.
  */
 
+#include <linux/bitfield.h>
+
 #include <drm/armada_drm.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
@@ -445,8 +447,8 @@ static int armada_overlay_get_property(struct drm_plane *plane,
 			     drm_to_overlay_state(state)->colorkey_ug,
 			     drm_to_overlay_state(state)->colorkey_vb, 0);
 	} else if (property == priv->colorkey_mode_prop) {
-		*val = (drm_to_overlay_state(state)->colorkey_mode &
-			CFG_CKMODE_MASK) >> ffs(CFG_CKMODE_MASK);
+		*val = FIELD_GET(CFG_CKMODE_MASK,
+				 drm_to_overlay_state(state)->colorkey_mode);
 	} else if (property == priv->brightness_prop) {
 		*val = drm_to_overlay_state(state)->brightness + 256;
 	} else if (property == priv->contrast_prop) {
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Russell King <linux@armlinux.org.uk>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: [PATCH resend] drm/armada: Fix off-by-one error in armada_overlay_get_property()
Date: Mon, 21 Nov 2022 16:43:14 +0100	[thread overview]
Message-ID: <788e97ac9b2aeee1941f274bf7b279b68c7592b6.1669045360.git.geert+renesas@glider.be> (raw)

As ffs() returns one more than the index of the first bit set (zero
means no bits set), the color key mode value is shifted one position too
much.

Fix this by using FIELD_GET() instead.

Fixes: c96103b6c49ff9a8 ("drm/armada: move colorkey properties into overlay plane state")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Compile-tested only.
---
 drivers/gpu/drm/armada/armada_overlay.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/armada/armada_overlay.c b/drivers/gpu/drm/armada/armada_overlay.c
index f21eb8fb76d87285..3b9bd8ecda137f6d 100644
--- a/drivers/gpu/drm/armada/armada_overlay.c
+++ b/drivers/gpu/drm/armada/armada_overlay.c
@@ -4,6 +4,8 @@
  *  Rewritten from the dovefb driver, and Armada510 manuals.
  */
 
+#include <linux/bitfield.h>
+
 #include <drm/armada_drm.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
@@ -445,8 +447,8 @@ static int armada_overlay_get_property(struct drm_plane *plane,
 			     drm_to_overlay_state(state)->colorkey_ug,
 			     drm_to_overlay_state(state)->colorkey_vb, 0);
 	} else if (property == priv->colorkey_mode_prop) {
-		*val = (drm_to_overlay_state(state)->colorkey_mode &
-			CFG_CKMODE_MASK) >> ffs(CFG_CKMODE_MASK);
+		*val = FIELD_GET(CFG_CKMODE_MASK,
+				 drm_to_overlay_state(state)->colorkey_mode);
 	} else if (property == priv->brightness_prop) {
 		*val = drm_to_overlay_state(state)->brightness + 256;
 	} else if (property == priv->contrast_prop) {
-- 
2.25.1


             reply	other threads:[~2022-11-21 15:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-21 15:43 Geert Uytterhoeven [this message]
2022-11-21 15:43 ` [PATCH resend] drm/armada: Fix off-by-one error in armada_overlay_get_property() Geert Uytterhoeven
2022-11-21 15:54 ` Russell King (Oracle)
2022-11-21 15:54   ` Russell King (Oracle)

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