Re: [PATCH] irqchip/imx-intmux: fix runtime PM teardown on remove

[Radu Rendec]

On Mon, 2026-09-14 at 21:42 +0800, Guangshuo Li wrote:
> 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")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> ---
>  drivers/irqchip/irq-imx-intmux.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 

+ Zhipeng

The patch looks good to me but I'm wondering if it's not a better idea
to fix it in a similar manner to the imx-irqsteer driver. Please see
https://lore.kernel.org/all/20260821101039.4037925-7-Zhipeng.wang_1@xxxxxxxxxxx/

The two drivers are already similar, so I think it makes sense to keep
them aligned. It would also address some of the issues that sashiko
flagged (probably, I haven't looked very closely).

> diff --git a/drivers/irqchip/irq-imx-intmux.c b/drivers/irqchip/irq-imx-intmux.c
> index 47c2681d138a..de2a8f98f625 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

-- 
Regards,
Radu