Re: [PATCH 2/2] PCI: meson: Add missing remove callback

From: Bjorn Helgaas <helgaas@kernel.org>
To: Shuvam Pandey <shuvampandey1@gmail.com>
Cc: "Jingoo Han" <jingoohan1@gmail.com>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Yue Wang" <yue.wang@amlogic.com>,
	"Neil Armstrong" <neil.armstrong@linaro.org>,
	"Rob Herring" <robh@kernel.org>,
	"Kevin Hilman" <khilman@baylibre.com>,
	"Jerome Brunet" <jbrunet@baylibre.com>,
	"Martin Blumenstingl" <martin.blumenstingl@googlemail.com>,
	"Fan Ni" <fan.ni@samsung.com>,
	"Shradha Todi" <shradha.t@samsung.com>,
	"Hanjie Lin" <hanjie.lin@amlogic.com>,
	linux-pci@vger.kernel.org, linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] PCI: meson: Add missing remove callback
Date: Thu, 11 Jun 2026 17:26:53 -0500	[thread overview]
Message-ID: <20260611222653.GA527114@bhelgaas> (raw)
In-Reply-To: <1a0c86ab264cdc1c79c917e984b90991af51d827.1779123847.git.shuvampandey1@gmail.com>

On Mon, May 18, 2026 at 10:44:18PM +0545, Shuvam Pandey wrote:
> meson_pcie_probe() powers on the PHY and registers the DesignWare host
> bridge with dw_pcie_host_init(), but the driver has no remove callback.
> On driver unbind or module unload, the driver core therefore proceeds to
> devres cleanup without first unregistering the host bridge or powering off
> the PHY.
> 
> Add a remove callback that deinitializes the DesignWare host bridge and
> powers off the PHY while device-managed resources are still valid.

What's the user-visible effect of this?  Does it avoid an oops?
Reduce power usage?

Of the 34 instances of .probe() in drivers/pci/controller/dwc/, on 12
implement .remove(), so if this fixes a problem, I'm wondering whether
other drivers have the same problem.

> Fixes: 9c0ef6d34fdb ("PCI: amlogic: Add the Amlogic Meson PCIe controller driver")
> Signed-off-by: Shuvam Pandey <shuvampandey1@gmail.com>
> ---
>  drivers/pci/controller/dwc/pci-meson.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
> index 0694084f6..c96e2244a 100644
> --- a/drivers/pci/controller/dwc/pci-meson.c
> +++ b/drivers/pci/controller/dwc/pci-meson.c
> @@ -451,6 +451,14 @@ static int meson_pcie_probe(struct platform_device *pdev)
>  	return ret;
>  }
>  
> +static void meson_pcie_remove(struct platform_device *pdev)
> +{
> +	struct meson_pcie *mp = platform_get_drvdata(pdev);
> +
> +	dw_pcie_host_deinit(&mp->pci.pp);
> +	meson_pcie_power_off(mp);
> +}
> +
>  static const struct of_device_id meson_pcie_of_match[] = {
>  	{
>  		.compatible = "amlogic,axg-pcie",
> @@ -464,6 +472,7 @@ MODULE_DEVICE_TABLE(of, meson_pcie_of_match);
>  
>  static struct platform_driver meson_pcie_driver = {
>  	.probe = meson_pcie_probe,
> +	.remove = meson_pcie_remove,
>  	.driver = {
>  		.name = "meson-pcie",
>  		.of_match_table = meson_pcie_of_match,
> -- 
> 2.50.1 (Apple Git-155)
> 
> 
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