FAILED: patch "[PATCH] irqchip/imx-intmux: Fix runtime PM teardown on remove" failed to apply to 5.15-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 5.15-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 <stable@vger.kernel.org>.

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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x b167c1a30e9e020e4c5e102c7a555943742c024b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107060640-failed-5.15-b167c1a30e9e@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

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

From b167c1a30e9e020e4c5e102c7a555943742c024b Mon Sep 17 00:00:00 2001
From: Guangshuo Li <lgs201920130244@gmail.com>
Date: Mon, 14 Sep 2026 21:42:11 +0800
Subject: [PATCH] irqchip/imx-intmux: Fix runtime PM teardown on remove

imx_intmux_probe() enables the IPG clock and then drops its runtime PM
reference with pm_runtime_put(). With CONFIG_PM enabled, the runtime
suspend callback disables the IPG clock. With CONFIG_PM disabled, the
clock remains enabled after probe.

imx_intmux_remove() accesses the CHANIER registers without first making
sure that the device is runtime active. The device may therefore be
runtime suspended with the IPG clock disabled when these registers are
accessed. In addition, the remove path only calls pm_runtime_disable()
and does not balance the clock enable when CONFIG_PM is disabled.

Resume the device and acquire a runtime PM reference before accessing
the registers. If resume fails, skip the register accesses but still
tear down the chained handlers and IRQ domains. Disable runtime PM
afterwards, drop the acquired reference without triggering another
runtime suspend, and explicitly disable the IPG clock.

This keeps the clock enabled while the hardware registers are accessed
and balances the clk_prepare_enable() performed during probe for both
CONFIG_PM configurations.

This issue was found by manual code inspection.

Fixes: bb403111e017 ("irqchip/imx-intmux: Implement intmux runtime power management")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260914134211.1734163-1-lgs201920130244@gmail.com
---
 drivers/irqchip/irq-imx-intmux.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-imx-intmux.c b/drivers/irqchip/irq-imx-intmux.c
index 47c2681d138a0..de2a8f98f6255 100644
--- a/drivers/irqchip/irq-imx-intmux.c
+++ b/drivers/irqchip/irq-imx-intmux.c
@@ -288,12 +288,16 @@ static int imx_intmux_probe(struct platform_device *pdev)
 static void imx_intmux_remove(struct platform_device *pdev)
 {
 	struct intmux_data *data = platform_get_drvdata(pdev);
-	int i;
+	int i, ret;
+
+	ret = pm_runtime_resume_and_get(&pdev->dev);
+	if (ret < 0)
+		dev_warn(&pdev->dev, "failed to resume device: %d\n", ret);
 
 	for (i = 0; i < data->channum; i++) {
 		/* disable all interrupt sources of this channel */
-		writel_relaxed(0, data->regs + CHANIER(i));
-
+		if (ret >= 0)
+			writel_relaxed(0, data->regs + CHANIER(i));
 		irq_set_chained_handler_and_data(data->irqchip_data[i].irq,
 						 NULL, NULL);
 
@@ -301,6 +305,11 @@ static void imx_intmux_remove(struct platform_device *pdev)
 	}
 
 	pm_runtime_disable(&pdev->dev);
+	if (ret >= 0) {
+		pm_runtime_put_noidle(&pdev->dev);
+		clk_disable_unprepare(data->ipg_clk);
+		pm_runtime_set_suspended(&pdev->dev);
+	}
 }
 
 #ifdef CONFIG_PM
-- 
2.53.0