diff options
| -rw-r--r-- | drivers/acpi/scan.c | 70 |
1 files changed, 54 insertions, 16 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index d670158a26c5..0476e90b2091 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -142,6 +142,53 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias, } /* + * acpi_companion_match() - Can we match via ACPI companion device + * @dev: Device in question + * + * Check if the given device has an ACPI companion and if that companion has + * a valid list of PNP IDs, and if the device is the first (primary) physical + * device associated with it. + * + * If multiple physical devices are attached to a single ACPI companion, we need + * to be careful. The usage scenario for this kind of relationship is that all + * of the physical devices in question use resources provided by the ACPI + * companion. A typical case is an MFD device where all the sub-devices share + * the parent's ACPI companion. In such cases we can only allow the primary + * (first) physical device to be matched with the help of the companion's PNP + * IDs. + * + * Additional physical devices sharing the ACPI companion can still use + * resources available from it but they will be matched normally using functions + * provided by their bus types (and analogously for their modalias). + */ +static bool acpi_companion_match(const struct device *dev) +{ + struct acpi_device *adev; + bool ret; + + adev = ACPI_COMPANION(dev); + if (!adev) + return false; + + if (list_empty(&adev->pnp.ids)) + return false; + + mutex_lock(&adev->physical_node_lock); + if (list_empty(&adev->physical_node_list)) { + ret = false; + } else { + const struct acpi_device_physical_node *node; + + node = list_first_entry(&adev->physical_node_list, + struct acpi_device_physical_node, node); + ret = node->dev == dev; + } + mutex_unlock(&adev->physical_node_lock); + + return ret; +} + +/* * Creates uevent modalias field for ACPI enumerated devices. * Because the other buses does not support ACPI HIDs & CIDs. * e.g. for a device with hid:IBM0001 and cid:ACPI0001 you get: @@ -149,20 +196,14 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias, */ int acpi_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env) { - struct acpi_device *acpi_dev; int len; - acpi_dev = ACPI_COMPANION(dev); - if (!acpi_dev) - return -ENODEV; - - /* Fall back to bus specific way of modalias exporting */ - if (list_empty(&acpi_dev->pnp.ids)) + if (!acpi_companion_match(dev)) return -ENODEV; if (add_uevent_var(env, "MODALIAS=")) return -ENOMEM; - len = create_modalias(acpi_dev, &env->buf[env->buflen - 1], + len = create_modalias(ACPI_COMPANION(dev), &env->buf[env->buflen - 1], sizeof(env->buf) - env->buflen); if (len <= 0) return len; @@ -179,18 +220,12 @@ EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias); */ int acpi_device_modalias(struct device *dev, char *buf, int size) { - struct acpi_device *acpi_dev; int len; - acpi_dev = ACPI_COMPANION(dev); - if (!acpi_dev) + if (!acpi_companion_match(dev)) return -ENODEV; - /* Fall back to bus specific way of modalias exporting */ - if (list_empty(&acpi_dev->pnp.ids)) - return -ENODEV; - - len = create_modalias(acpi_dev, buf, size -1); + len = create_modalias(ACPI_COMPANION(dev), buf, size -1); if (len <= 0) return len; buf[len++] = '\n'; @@ -853,6 +888,9 @@ const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids, if (!ids || !handle || acpi_bus_get_device(handle, &adev)) return NULL; + if (!acpi_companion_match(dev)) + return NULL; + return __acpi_match_device(adev, ids); } EXPORT_SYMBOL_GPL(acpi_match_device); |