linux-kernel - Re: [PATCH] backlight: qcom-wled: fix unbalanced ovp irq enable

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Message-ID: <5569198e-5548-48f7-b64e-b7574ea59691@oss.qualcomm.com>
Date: Tue, 21 Oct 2025 11:25:09 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: foss@...lselvaraj.com, Lee Jones <lee@...nel.org>,
        Daniel Thompson <danielt@...nel.org>,
        Jingoo Han <jingoohan1@...il.com>, Helge Deller <deller@....de>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] backlight: qcom-wled: fix unbalanced ovp irq enable

On 10/21/25 9:33 AM, Joel Selvaraj via B4 Relay wrote:
> From: Joel Selvaraj <foss@...lselvaraj.com>
> 
> In Xiaomi Poco F1 and at least few other devices, the qcom wled driver
> triggers unbalanced ovp irq enable warning like the following during
> boot up.
> 
> [    1.151677] ------------[ cut here ]------------
> [    1.151680] Unbalanced enable for IRQ 176
> [    1.151693] WARNING: CPU: 0 PID: 160 at kernel/irq/manage.c:774 __enable_irq+0x50/0x80
> [    1.151710] Modules linked in:
> [    1.151717] CPU: 0 PID: 160 Comm: kworker/0:11 Not tainted 5.17.0-sdm845 #4
> [    1.151724] Hardware name: Xiaomi Pocophone F1 (DT)
> [    1.151728] Workqueue: events wled_ovp_work
> ...<snip>...
> [    1.151833] Call trace:
> [    1.151836]  __enable_irq+0x50/0x80
> [    1.151841]  enable_irq+0x48/0xa0
> [    1.151846]  wled_ovp_work+0x18/0x24
> [    1.151850]  process_one_work+0x1d0/0x350
> [    1.151858]  worker_thread+0x13c/0x460
> [    1.151862]  kthread+0x110/0x114
> [    1.151868]  ret_from_fork+0x10/0x20
> [    1.151876] ---[ end trace 0000000000000000 ]---
> 
> Fix it by storing and checking the state of ovp irq before enabling and
> disabling it.
> 
> Signed-off-by: Joel Selvaraj <foss@...lselvaraj.com>
> ---
> I am not entirely sure if this is the ideal fix. But this patch provides
> an okayish stopgap solution till we can properly fix it. I am open to 
> try a different approach if there is any suggestion.
> ---
>  drivers/video/backlight/qcom-wled.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
> index a63bb42c8f8b0333cd6d0ddc5bda93916da3fef3..36e2fe5c5fa37cfb8750254a75eff612741983c8 100644
> --- a/drivers/video/backlight/qcom-wled.c
> +++ b/drivers/video/backlight/qcom-wled.c
> @@ -197,6 +197,7 @@ struct wled {
>  	bool disabled_by_short;
>  	bool has_short_detect;
>  	bool cabc_disabled;
> +	bool ovp_irq_disabled;

This is generally "..irq_enabled"

>  	int short_irq;
>  	int ovp_irq;
>  
> @@ -294,7 +295,10 @@ static void wled_ovp_work(struct work_struct *work)
>  {
>  	struct wled *wled = container_of(work,
>  					 struct wled, ovp_work.work);
> -	enable_irq(wled->ovp_irq);
> +	if (wled->ovp_irq_disabled) {
> +		enable_irq(wled->ovp_irq);
> +		wled->ovp_irq_disabled = false;

You can also create a short wrapper like ovp_irq_enable() that would do
it internally (making it harder to overlook assigning this variable)

Konrad