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Date: Tue, 19 Dec 2023 14:15:58 -0800
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Esther Shimanovich <eshimanovich@chromium.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, Rajat Jain <rajatja@google.com>
Subject: Re: [PATCH v2] PCI: Relabel JHL6540 on Lenovo X1 Carbon 7,8
Message-ID: <ZYIWHjr0U08tIHOk@google.com>
References: <20231219-thunderbolt-pci-patch-4-v2-1-ec2d7af45a9b@chromium.org>
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In-Reply-To: <20231219-thunderbolt-pci-patch-4-v2-1-ec2d7af45a9b@chromium.org>

Hi Esther,

On Tue, Dec 19, 2023 at 04:34:33PM -0500, Esther Shimanovich wrote:
> +static void carbon_X1_fixup_relabel_alpine_ridge(struct pci_dev *dev)
> +{
> +	if (!dmi_match(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 7th") &&
> +	    !dmi_match(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon Gen 8"))
> +		return;
> +
> +	/* Is this JHL6540 PCI component embedded in a Lenovo device? */
> +	if (dev->subsystem_vendor != 0x17aa)
> +		return;

Maybe use PCI_VENDOR_ID_LENOVO and move the check first - it is cheaper
than string comparison. In general, symbolic constants are preferred to
magic numbers.

Actually, do we really need to check DMI given the checks below?

> +
> +	/* Is this JHL6540 PCI component embedded in an X1 Carbon Gen 7/8? */
> +	if (dev->subsystem_device != 0x22be && // Gen 8
> +	    dev->subsystem_device != 0x2292) { // Gen 7
> +		return;
> +	}
> +
> +	dev_set_removable(&dev->dev, DEVICE_FIXED);
> +
> +	/* Not all 0x15d3 components are external facing */
> +	if (dev->device == 0x15d3 &&

Again, maybe PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_BRIDGE?

Thanks.

-- 
Dmitry