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

Hans de Goede
2026-04-17T17:35:47Z

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@gmail.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>

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;