Re: [PATCH v3 1/5] platform/x86: intel_lpss: add resource conflict quirk for Dell Latitude 5285

[Hans de Goede]

Hi,

On 17-Apr-26 18:32, Thierry Chatard wrote:
> 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.
> 
> Add a DMI quirk that selects IGNORE_RESOURCE_CONFLICTS for INT3446 on this
> machine, matching the existing pattern used by other LPSS quirks.
> 
> Signed-off-by: Thierry Chatard <tchatard@xxxxxxxxx>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <johannes.goede@xxxxxxxxxxxxxxxx>

Regards,

Hans


> ---
>  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..7d0964848 100644
> --- a/drivers/mfd/intel-lpss-acpi.c
> +++ b/drivers/mfd/intel-lpss-acpi.c
> @@ -13,6 +13,8 @@
>  #include <linux/ioport.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/module.h>
> +#include <linux/acpi.h>
> +#include <linux/dmi.h>
>  #include <linux/pm.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/platform_device.h>
> @@ -52,6 +54,15 @@ static const struct intel_lpss_platform_info spt_i2c_info = {
>  	.swnode = &spt_i2c_node,
>  };
>  
> +/* Same as spt_i2c_info but with QUIRK_IGNORE_RESOURCE_CONFLICTS for Dell 5285
> + * where ACPI GEXP device conflicts with I2C4 (INT3446) MMIO resources.
> + */
> +static const struct intel_lpss_platform_info spt_i2c_info_ignore_conflicts = {
> +	.clk_rate = 120000000,
> +	.swnode = &spt_i2c_node,
> +	.quirks = QUIRK_IGNORE_RESOURCE_CONFLICTS,
> +};
> +
>  static const struct property_entry uart_properties[] = {
>  	PROPERTY_ENTRY_U32("reg-io-width", 4),
>  	PROPERTY_ENTRY_U32("reg-shift", 2),
> @@ -172,6 +183,16 @@ static const struct acpi_device_id intel_lpss_acpi_ids[] = {
>  };
>  MODULE_DEVICE_TABLE(acpi, intel_lpss_acpi_ids);
>  
> +static const struct dmi_system_id dell5285_lpss_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;
> @@ -182,6 +203,17 @@ static int intel_lpss_acpi_probe(struct platform_device *pdev)
>  	if (!data)
>  		return -ENODEV;
>  
> +	/* Apply IGNORE_RESOURCE_CONFLICTS for I2C4 on Dell Latitude 5285.
> +	 * The ACPI GEXP device conflicts with I2C4 (INT3446) MMIO resources
> +	 * due to a BIOS bug where both use the same SB04 variable.
> +	 */
> +	if (data == &spt_i2c_info &&
> +	    acpi_dev_hid_uid_match(ACPI_COMPANION(&pdev->dev), "INT3446", NULL) &&
> +	    dmi_check_system(dell5285_lpss_dmi)) {
> +		dev_info(&pdev->dev, "Dell 5285: applying IGNORE_RESOURCE_CONFLICTS for I2C4\n");
> +		data = &spt_i2c_info_ignore_conflicts;
> +	}
> +
>  	info = devm_kmemdup(&pdev->dev, data, sizeof(*info), GFP_KERNEL);
>  	if (!info)
>  		return -ENOMEM;