Re: [PATCH v8 1/6] platform/x86: intel_lpss: add resource conflict quirk for Dell Latitude 5285

[Ilpo Järvinen]

On Wed, 26 Aug 2026, Thierry Chatard wrote:

Why is this platform/x86: prefixed??

--
 i.

> The Dell Latitude 5285 2-in-1 has a BIOS bug where the ACPI GEXP device
> and the I2C4 controller (INT3446) both claim the same MMIO region via the
> shared SB04 variable. This causes intel_lpss_acpi to fail binding to I2C4
> with -EBUSY, preventing the front camera (OV5670) sensor from being
> registered.
> 
> Match the affected machine by DMI and the affected device by ACPI ID,
> carrying QUIRK_IGNORE_RESOURCE_CONFLICTS in the ACPI match data and
> applying it to the per-device info in probe. This follows the quirk
> organisation used by the PCI counterpart.
> 
> Signed-off-by: Thierry Chatard <tchatard@xxxxxxxxx>
> ---
>  drivers/mfd/intel-lpss-acpi.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c
> index 63406026d..1ac1dcc41 100644
> --- a/drivers/mfd/intel-lpss-acpi.c
> +++ b/drivers/mfd/intel-lpss-acpi.c
> @@ -8,7 +8,9 @@
>   *          Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/device.h>
> +#include <linux/dmi.h>
>  #include <linux/gfp_types.h>
>  #include <linux/ioport.h>
>  #include <linux/mod_devicetable.h>
> @@ -172,6 +174,27 @@ static const struct acpi_device_id intel_lpss_acpi_ids[] = {
>  };
>  MODULE_DEVICE_TABLE(acpi, intel_lpss_acpi_ids);
>  
> +/*
> + * Devices that need a quirk applied only on the machines matched by
> + * intel_lpss_quirk_dmi[] below. The quirk to apply is carried in the
> + * matching entry's driver_data.
> + */
> +static const struct acpi_device_id intel_lpss_acpi_quirk_ids[] = {
> +	/* Dell Latitude 5285: ACPI GEXP device conflicts with I2C4 (INT3446) */
> +	{ "INT3446", QUIRK_IGNORE_RESOURCE_CONFLICTS },
> +	{ }
> +};
> +
> +static const struct dmi_system_id intel_lpss_quirk_dmi[] = {
> +	{
> +		.matches = {
> +			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> +			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 5285"),
> +		},
> +	},
> +	{ }
> +};
> +
>  static int intel_lpss_acpi_probe(struct platform_device *pdev)
>  {
>  	const struct intel_lpss_platform_info *data;
> @@ -186,6 +209,15 @@ static int intel_lpss_acpi_probe(struct platform_device *pdev)
>  	if (!info)
>  		return -ENOMEM;
>  
> +	/* Apply per-device quirks that are only needed on certain machines */
> +	if (dmi_check_system(intel_lpss_quirk_dmi)) {
> +		const struct acpi_device_id *id;
> +
> +		id = acpi_match_device(intel_lpss_acpi_quirk_ids, &pdev->dev);
> +		if (id)
> +			info->quirks |= id->driver_data;
> +	}
> +
>  	/* No need to check mem and irq here as intel_lpss_probe() does it for us */
>  	info->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	info->irq = platform_get_irq(pdev, 0);
>