The ACPI scan code currently does not honor _DEP lists, except for ACPI battery nodes. This is an issue on some devices, where some of the methods used during device-addition may rely on OpRegions of other devices. An example of this is the Acer Switch 10E SW3-016 model. The _HID method of the ACPI node for the UART attached Bluetooth, reads GPIOs to detect the installed wifi chip and update the _HID for the Bluetooth's ACPI node accordingly. The current ACPI scan code calls _HID before the GPIO controller's OpRegions are available, leading to the wrong _HID being used and Bluetooth not working. This splits the scanning into 2 steps, deferring the addition of some devices which need access to OpRegions of other devices during scanning to the second step. This initial implementation takes a very simple approach to identify which devices need to have their device-addition deferred. It uses a static lists of HIDs for this. This list is initially populated with the HID reported for the Bluetooth on the Acer SW3-016. This uses the HID reported when the GPIO OpRegions are not yet available! A more elaborate approach, which actually looks at the _DEP list will be added by a follow up patch. This other approach has a big chance of causing regressions, so for now it will be hidden behind a kernel commandline option. Which is why the KISS approach chosen here is needed to fix the issue at hand, so that things will work OOTB on affected devices. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1665610 Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> --- drivers/acpi/scan.c | 65 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 7dde66222648..407c8536568b 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -42,6 +42,15 @@ DEFINE_MUTEX(acpi_device_lock); LIST_HEAD(acpi_wakeup_device_list); static DEFINE_MUTEX(acpi_hp_context_lock); +/* + * Variables for the new 2 step scan scheme: + * Step 1. Add all devices for which acpi_should_defer_add() returns false + * Step 2. Add devices deferred during phase 1. + * These are protected by the acpi_scan_lock. + */ +static bool acpi_check_defer_add; +static LIST_HEAD(acpi_deferred_devices); + /* * The UART device described by the SPCR table is the only object which needs * special-casing. Everything else is covered by ACPI namespace paths in STAO @@ -55,6 +64,11 @@ struct acpi_dep_data { acpi_handle slave; }; +struct acpi_deferred_dev { + struct list_head node; + acpi_handle handle; +}; + void acpi_scan_lock_acquire(void) { mutex_lock(&acpi_scan_lock); @@ -741,6 +755,16 @@ static const char * const acpi_ignore_dep_hids[] = { NULL }; +/* + * List of HIDs for which we defer adding them to the second step of the + * scanning of the root, because some of their methods used during addition + * depend on OpRegions registered by the drivers for other ACPI devices. + */ +static const char * const acpi_defer_add_hids[] = { + "BCM2E5B", /* Acer SW3-016 bluetooth HID when GPIO OpRegs or not available yet */ + NULL +}; + static struct acpi_device *acpi_bus_get_parent(acpi_handle handle) { struct acpi_device *device = NULL; @@ -1631,18 +1655,42 @@ void acpi_device_add_finalize(struct acpi_device *device) kobject_uevent(&device->dev.kobj, KOBJ_ADD); } +static bool acpi_should_defer_add(acpi_handle handle, struct acpi_device_info *info) +{ + if (!acpi_check_defer_add || !info) + return false; + + if (acpi_info_matches_hids(info, acpi_defer_add_hids)) + return true; + + return false; +} + static int acpi_add_single_object(struct acpi_device **child, acpi_handle handle, int type, unsigned long long sta) { int result; struct acpi_device *device; + struct acpi_deferred_dev *deferred_dev; struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; struct acpi_device_info *info = NULL; if (handle != ACPI_ROOT_OBJECT && type == ACPI_BUS_TYPE_DEVICE) acpi_get_object_info(handle, &info); + if (acpi_should_defer_add(handle, info)) { + kfree(info); + + deferred_dev = kzalloc(sizeof(*deferred_dev), GFP_KERNEL); + if (!deferred_dev) + return -ENOMEM; + + deferred_dev->handle = handle; + list_add_tail(&deferred_dev->node, &acpi_deferred_devices); + return -EPROBE_DEFER; + } + device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL); if (!device) { printk(KERN_ERR PREFIX "Memory allocation error\n"); @@ -2201,6 +2249,7 @@ int __init acpi_scan_init(void) int result; acpi_status status; struct acpi_table_stao *stao_ptr; + struct acpi_deferred_dev *deferred_dev, *tmp; acpi_pci_root_init(); acpi_pci_link_init(); @@ -2248,7 +2297,9 @@ int __init acpi_scan_init(void) /* * Enumerate devices in the ACPI namespace. */ + acpi_check_defer_add = true; result = acpi_bus_scan(ACPI_ROOT_OBJECT); + acpi_check_defer_add = false; if (result) goto cleanup; @@ -2256,6 +2307,15 @@ int __init acpi_scan_init(void) if (result) goto cleanup; + list_for_each_entry_safe(deferred_dev, tmp, &acpi_deferred_devices, node) { + result = acpi_bus_scan(deferred_dev->handle); + if (result) + goto cleanup; + + list_del(&deferred_dev->node); + kfree(deferred_dev); + } + /* Fixed feature devices do not exist on HW-reduced platform */ if (!acpi_gbl_reduced_hardware) { result = acpi_bus_scan_fixed(); @@ -2275,6 +2335,11 @@ int __init acpi_scan_init(void) put_device(&acpi_root->dev); } + list_for_each_entry_safe(deferred_dev, tmp, &acpi_deferred_devices, node) { + list_del(&deferred_dev->node); + kfree(deferred_dev); + } + mutex_unlock(&acpi_scan_lock); return result; } -- 2.28.0
