* [PATCH 1/2] acpi: Use METHOD_NAME__UID instead of open-coded _UID
2026-08-13 2:41 [PATCH 0/2] acpi: add kernel option to skip binding drivers to certain devices dmukhin
@ 2026-08-13 2:41 ` dmukhin
2026-08-13 2:41 ` [PATCH 2/2] acpi: bus: Introduce acpi.skip_ids= boot parameter dmukhin
1 sibling, 0 replies; 5+ messages in thread
From: dmukhin @ 2026-08-13 2:41 UTC (permalink / raw)
To: Rafael J . Wysocki, Len Brown, linux-acpi, linux-kernel; +Cc: Denis Mukhin
From: Denis Mukhin <dmukhin@ford.com>
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
drivers/acpi/acpi_processor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 00775b91bd41..cb39e4a30f0e 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -739,7 +739,7 @@ static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
break;
case ACPI_TYPE_DEVICE:
- status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
+ status = acpi_evaluate_integer(handle, METHOD_NAME__UID, NULL, &uid);
if (ACPI_FAILURE(status))
goto err;
break;
--
2.54.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] acpi: bus: Introduce acpi.skip_ids= boot parameter
2026-08-13 2:41 [PATCH 0/2] acpi: add kernel option to skip binding drivers to certain devices dmukhin
2026-08-13 2:41 ` [PATCH 1/2] acpi: Use METHOD_NAME__UID instead of open-coded _UID dmukhin
@ 2026-08-13 2:41 ` dmukhin
2026-08-13 10:09 ` Rafael J. Wysocki (Intel)
1 sibling, 1 reply; 5+ messages in thread
From: dmukhin @ 2026-08-13 2:41 UTC (permalink / raw)
To: Rafael J . Wysocki, Len Brown, linux-acpi, linux-kernel; +Cc: Denis Mukhin
From: Denis Mukhin <dmukhin@ford.com>
In virtualized environments it is possible that a device managed by the
hypervisor or another VM is described in the ACPI tables. In these
cases, binding a device driver to it can cause functional issues.
To resolve device ownership conflicts, skip enumeration of ACPI devices
whose ACPI IDs match entries specified via a new boot-time parameter:
acpi.skip_ids=<HID[:UID]>[,<HID[:UID]>...]
This parameter may also be used when a single kernel image must support
both bare-metal and virtualized environments - for example, when the
image is shared across multiple VMs and only selected platform devices
are exposed through passthrough.
Note, a single driver may support multiple devices and only a subset of
those devices may require exclusion (for example, ABCD0020:00 but not
ABCD0020:01). As a result, existing 'initcall_blacklist=' is not an
appropriate solution to resolve the ownership conflict.
Add brief explanation for apci.skip_ids= in the kernel command line
documentation.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
.../admin-guide/kernel-parameters.txt | 5 ++
drivers/acpi/bus.c | 60 +++++++++++++++++--
2 files changed, 61 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 3d35270dddef..a2d4bd9e37b9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -195,6 +195,11 @@ Kernel parameters
ACPI firmware problems, as the system might behave erratically
after having encountered a fatal ACPI error.
+ acpi.skip_ids= [ACPI] Skip enumeration of ACPI devices whose HID[:UID]
+ matches an entry in the given comma-separated list
+ (up to 16 entries).
+ Format: HID[:UID][,HID[:UID]...]
+
acpi_enforce_resources= [ACPI]
{ strict | lax | no }
Check for resource conflicts between native drivers
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index a30a904f6535..86dba970bfc2 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -38,6 +38,15 @@ struct acpi_device *acpi_root;
struct proc_dir_entry *acpi_root_dir;
EXPORT_SYMBOL(acpi_root_dir);
+#define ACPI_MAX_SKIP_IDS 16 /* Arbitrary limit. */
+
+static char *acpi_skip_ids[ACPI_MAX_SKIP_IDS];
+static int acpi_skip_num;
+module_param_array_named(skip_ids, acpi_skip_ids, charp,
+ &acpi_skip_num, 0444);
+MODULE_PARM_DESC(skip_ids,
+ "Skip binding ACPI drivers to devices with matching _HID[:_UID]");
+
#ifdef CONFIG_X86
#ifdef CONFIG_ACPI_CUSTOM_DSDT
static inline int set_copy_dsdt(const struct dmi_system_id *id)
@@ -1008,6 +1017,9 @@ static bool __acpi_match_device(const struct acpi_device *device,
{
const struct acpi_device_id *id;
struct acpi_hardware_id *hwid;
+ struct acpi_device_info *info = NULL;
+ bool ret = false;
+ int i;
/*
* If the device is not present, it is unnecessary to load device
@@ -1016,8 +1028,42 @@ static bool __acpi_match_device(const struct acpi_device *device,
if (!device || !device->status.present)
return false;
+ if (acpi_skip_num) {
+ acpi_status status;
+
+ status = acpi_get_object_info(device->handle, &info);
+ if (ACPI_FAILURE(status))
+ info = NULL;
+ }
+
list_for_each_entry(hwid, &device->pnp.ids, list) {
- /* First, check the ACPI/PNP IDs provided by the caller. */
+ /* First, check whether device ACPI ID is in the skip list. */
+ for (i = 0; i < acpi_skip_num; i++) {
+ char with_uid[MAX_ACPI_DEVICE_NAME_LEN];
+ u32 uid;
+
+ if (!strcasecmp(acpi_skip_ids[i], hwid->id)) {
+ ret = false;
+ goto out;
+ }
+
+ if (!info || !(info->valid & ACPI_VALID_UID))
+ continue;
+
+ if (kstrtou32(info->unique_id.string, 0, &uid))
+ snprintf(with_uid, sizeof(with_uid), "%s:%s",
+ hwid->id, info->unique_id.string);
+ else
+ snprintf(with_uid, sizeof(with_uid), "%s:%02x",
+ hwid->id, uid);
+
+ if (!strcasecmp(acpi_skip_ids[i], with_uid)) {
+ ret = false;
+ goto out;
+ }
+ }
+
+ /* Second, check the ACPI/PNP IDs provided by the caller. */
if (acpi_ids) {
for (id = acpi_ids; id->id[0] || id->cls; id++) {
if (id->id[0] && !strcmp((char *)id->id, hwid->id))
@@ -1031,12 +1077,18 @@ static bool __acpi_match_device(const struct acpi_device *device,
* Next, check ACPI_DT_NAMESPACE_HID and try to match the
* "compatible" property if found.
*/
- if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id))
- return acpi_of_match_device(device, of_ids, of_id);
+ if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id)) {
+ ret = acpi_of_match_device(device, of_ids, of_id);
+ goto out;
+ }
}
- return false;
+
+out:
+ kfree(info);
+ return ret;
out_acpi_match:
+ kfree(info);
if (acpi_id)
*acpi_id = id;
return true;
--
2.54.0
^ permalink raw reply related [flat|nested] 5+ messages in thread