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FAILED: patch "[PATCH] drm/i915/power: fix size for for_each_set_bit() in abox" failed to apply to 6.12-stable tree

PATCH New [email protected] 2 participants 2 messages Sep 13, 2025 – Sep 14, 2025

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Stable branch DRM drivers Intel i915 Intel DRM display for xe and i915 drivers
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author maintainer
#0 lore raw

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x cfa7b7659757f8d0fc4914429efa90d0d2577dd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025091354-plenty-unlined-c98e@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From cfa7b7659757f8d0fc4914429efa90d0d2577dd7 Mon Sep 17 00:00:00 2001
From: Jani Nikula <[email protected]>
Date: Fri, 5 Sep 2025 13:41:49 +0300
Subject: [PATCH] drm/i915/power: fix size for for_each_set_bit() in abox
iteration
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

for_each_set_bit() expects size to be in bits, not bytes. The abox mask iteration uses bytes, but it works by coincidence, because the local variable holding the mask is unsigned long, and the mask only ever has bit 2 as the highest bit. Using a smaller type could lead to subtle and very hard to track bugs.

Fixes 62afef2811e4 ("drm/i915/rkl: RKL uses ABOX0 for pixel transfers")
Cc Ville Syrjälä <[email protected]>
Cc Matt Roper <[email protected]>
Cc [email protected] # v5.9+
Reviewed-by Matt Roper <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Jani Nikula <[email protected]>
(cherry picked from commit 7ea3baa6efe4bb93d11e1c0e6528b1468d7debf6)
Signed-off-by Tvrtko Ursulin <[email protected]>
drivers/gpu/drm/i915/display/intel_display_power.c +3 -3
index 273054c22325..c92f3e736228 100644
@@ -1172,7 +1172,7 @@ static void icl_mbus_init(struct intel_display *display)
 	if (DISPLAY_VER(display) == 12)
 		abox_regs |= BIT(0);
 
-	for_each_set_bit(i, &abox_regs, sizeof(abox_regs))
+	for_each_set_bit(i, &abox_regs, BITS_PER_TYPE(abox_regs))
 		intel_de_rmw(display, MBUS_ABOX_CTL(i), mask, val);
 }
 

@@ -1629,11 +1629,11 @@ static void tgl_bw_buddy_init(struct intel_display *display)
 	if (table[config].page_mask == 0) {
 		drm_dbg_kms(display->drm,
 			    "Unknown memory configuration; disabling address buddy logic.\n");
-		for_each_set_bit(i, &abox_mask, sizeof(abox_mask))
+		for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask))
 			intel_de_write(display, BW_BUDDY_CTL(i),
 				       BW_BUDDY_DISABLE);
 	} else {
-		for_each_set_bit(i, &abox_mask, sizeof(abox_mask)) {
+		for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask)) {
 			intel_de_write(display, BW_BUDDY_PAGE_MASK(i),
 				       table[config].page_mask);
maintainer
#1 lore raw

PATCH 1/1 drm/i915/power: fix size for for_each_set_bit() in abox iteration

From: Jani Nikula <[email protected]>

[ Upstream commit cfa7b7659757f8d0fc4914429efa90d0d2577dd7 ]

for_each_set_bit() expects size to be in bits, not bytes. The abox mask iteration uses bytes, but it works by coincidence, because the local variable holding the mask is unsigned long, and the mask only ever has bit 2 as the highest bit. Using a smaller type could lead to subtle and very hard to track bugs.

Fixes 62afef2811e4 ("drm/i915/rkl: RKL uses ABOX0 for pixel transfers")
Cc Ville Syrjälä <[email protected]>
Cc Matt Roper <[email protected]>
Cc [email protected] # v5.9+
Reviewed-by Matt Roper <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Jani Nikula <[email protected]>
(cherry picked from commit 7ea3baa6efe4bb93d11e1c0e6528b1468d7debf6)
Signed-off-by Tvrtko Ursulin <[email protected]>
[ adapted struct intel_display *display parameters to struct drm_i915_private *dev_priv ]
Signed-off-by Sasha Levin <[email protected]>
---
 drivers/gpu/drm/i915/display/intel_display_power.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
drivers/gpu/drm/i915/display/intel_display_power.c +3 -3
index ef2fdbf973460..85335d8dfec11 100644
@@ -1150,7 +1150,7 @@ static void icl_mbus_init(struct drm_i915_private *dev_priv)
 	if (DISPLAY_VER(dev_priv) == 12)
 		abox_regs |= BIT(0);
 
-	for_each_set_bit(i, &abox_regs, sizeof(abox_regs))
+	for_each_set_bit(i, &abox_regs, BITS_PER_TYPE(abox_regs))
 		intel_de_rmw(dev_priv, MBUS_ABOX_CTL(i), mask, val);
 }
 

@@ -1603,11 +1603,11 @@ static void tgl_bw_buddy_init(struct drm_i915_private *dev_priv)
 	if (table[config].page_mask == 0) {
 		drm_dbg(&dev_priv->drm,
 			"Unknown memory configuration; disabling address buddy logic.\n");
-		for_each_set_bit(i, &abox_mask, sizeof(abox_mask))
+		for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask))
 			intel_de_write(dev_priv, BW_BUDDY_CTL(i),
 				       BW_BUDDY_DISABLE);
 	} else {
-		for_each_set_bit(i, &abox_mask, sizeof(abox_mask)) {
+		for_each_set_bit(i, &abox_mask, BITS_PER_TYPE(abox_mask)) {
 			intel_de_write(dev_priv, BW_BUDDY_PAGE_MASK(i),
 				       table[config].page_mask);
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