Re: [PATCH v2 07/24] arm64: dts: qcom: sm8150: Reduce OS PDC DRV span to 0x10000

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Reducing the PDC `reg` size to 0x10000 in the Device Tree triggers a persistent boot warning and fails to actually reduce the mapped region.
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commit 0bc4a6740625a7680dd3bd2099be3c1e864d5c1a
Author: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

arm64: dts: qcom: sm8150: Reduce OS PDC DRV span to 0x10000

This commit reduces the OS PDC DRV register window size from 0x30000 to
0x10000 in the sm8150 device tree.

> diff --git a/arch/arm64/boot/dts/qcom/sm8150.dtsi b/arch/arm64/boot/dts/qcom/sm8150.dtsi
> index 0e101096209ab..661848ef5eee2 100644
> --- a/arch/arm64/boot/dts/qcom/sm8150.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sm8150.dtsi
> @@ -4174,7 +4174,7 @@ dispcc: clock-controller@af00000 {
>  
>  		pdc: interrupt-controller@b220000 {
>  			compatible = "qcom,sm8150-pdc", "qcom,pdc";
> -			reg = <0 0x0b220000 0 0x30000>;
> +			reg = <0 0x0b220000 0 0x10000>;

[Severity: Medium]
Will this trigger a persistent boot warning and fail to actually reduce the
mapped region?

Looking at the qcom-pdc driver in drivers/irqchip/qcom-pdc.c, it contains
fallback logic that enforces a minimum resource size of QCOM_PDC_SIZE
(0x30000):

	res_size = max_t(resource_size_t, resource_size(res), QCOM_PDC_SIZE);

If the size provided by the device tree is less than 0x30000, it prints
a warning on boot:

	if (res_size > resource_size(res))
		pr_warn("%pOF: invalid reg size, please fix DT\n", np);

Because 0x10000 is smaller than 0x30000, won't this cause the driver to
print the warning on every boot while still remapping the full 0x30000
bytes anyway? 

Does the driver's fallback logic need to be updated before applying this
device tree change?

>  			qcom,pdc-ranges = <0 480 94>, <94 609 31>,
>  					  <125 63 1>;
>  			#interrupt-cells = <2>;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260527094333.2311731-1-mukesh.ojha@oss.qualcomm.com?part=7