diff options
| author | James Morse <james.morse@arm.com> | 2023-02-24 17:26:37 +0000 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2024-01-30 10:57:24 +0000 |
| commit | 597601f6707377a796d4a6304d15b2dead28c93e (patch) | |
| tree | 223d916e3e34f0e588521c9ce4041a029ad1d72e /drivers/acpi/device_sysfs.c | |
| parent | 41bccc98fb7931d63d03f326a746ac4d429c1dd3 (diff) | |
ACPI: Only enumerate enabled (or functional) processor devices
Today the ACPI enumeration code 'visits' all devices that are present.
This is a problem for arm64, where CPUs are always present, but not
always enabled. When a device-check occurs because the firmware-policy
has changed and a CPU is now enabled, the following error occurs:
| acpi ACPI0007:48: Enumeration failure
This is ultimately because acpi_dev_ready_for_enumeration() returns
true for a device that is not enabled. The ACPI Processor driver
will not register such CPUs as they are not 'decoding their resources'.
ACPI allows a device to be functional instead of maintaining the
present and enabled bit, but we can't simply check the enabled bit
for all devices since firmware can be buggy.
If ACPI indicates that the device is present and enabled, then all well
and good, we can enumate it. However, if the device is present and not
enabled, then we also check whether the device is a processor device
to limit the impact of this new check to just processor devices.
This avoids enumerating present && functional processor devices that
are not enabled.
Signed-off-by: James Morse <james.morse@arm.com>
Co-developed-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Incorporate comment suggestion by Gavin Shan.
Changes since RFC v3:
* Fixed "sert" typo.
Changes since RFC v3 (smaller series):
* Restrict checking the enabled bit to processor devices, update
commit comments.
* Use Rafael's suggestion in
https://lore.kernel.org/r/5760569.DvuYhMxLoT@kreacher
* Updated with a fix - see:
https://lore.kernel.org/all/Zbe8WQRASx6D6RaG@shell.armlinux.org.uk/
Diffstat (limited to 'drivers/acpi/device_sysfs.c')
| -rw-r--r-- | drivers/acpi/device_sysfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c index 23373faa35ec..a0256d2493a7 100644 --- a/drivers/acpi/device_sysfs.c +++ b/drivers/acpi/device_sysfs.c @@ -141,7 +141,7 @@ static int create_pnp_modalias(const struct acpi_device *acpi_dev, char *modalia struct acpi_hardware_id *id; /* Avoid unnecessarily loading modules for non present devices. */ - if (!acpi_device_is_present(acpi_dev)) + if (!acpi_dev_ready_for_enumeration(acpi_dev)) return 0; /* |