From a383b68d9fe9864c4d3b86f67ad6488f58136435 Mon Sep 17 00:00:00 2001 From: Yasuaki Ishimatsu Date: Wed, 3 Sep 2014 13:39:13 +0900 Subject: ACPI / scan: not cache _SUN value in struct acpi_device_pnp The _SUN device indentification object is not guaranteed to return the same value every time it is executed, so we should not cache its return value, but rather execute it every time as needed. If it is cached, an incorrect stale value may be used in some situations. This issue was exposed by commit 202317a573b2 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace). Fix it by avoiding to cache the return value of _SUN. Fixes: 202317a573b2 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace) Signed-off-by: Yasuaki Ishimatsu Cc: 3.14+ # 3.14+ [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'drivers') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 9a9298994e26..3bf7764659a4 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -667,8 +667,14 @@ static ssize_t acpi_device_sun_show(struct device *dev, struct device_attribute *attr, char *buf) { struct acpi_device *acpi_dev = to_acpi_device(dev); + acpi_status status; + unsigned long long sun; + + status = acpi_evaluate_integer(acpi_dev->handle, "_SUN", NULL, &sun); + if (ACPI_FAILURE(status)) + return -ENODEV; - return sprintf(buf, "%lu\n", acpi_dev->pnp.sun); + return sprintf(buf, "%llu\n", sun); } static DEVICE_ATTR(sun, 0444, acpi_device_sun_show, NULL); @@ -690,7 +696,6 @@ static int acpi_device_setup_files(struct acpi_device *dev) { struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; acpi_status status; - unsigned long long sun; int result = 0; /* @@ -731,14 +736,10 @@ static int acpi_device_setup_files(struct acpi_device *dev) if (dev->pnp.unique_id) result = device_create_file(&dev->dev, &dev_attr_uid); - status = acpi_evaluate_integer(dev->handle, "_SUN", NULL, &sun); - if (ACPI_SUCCESS(status)) { - dev->pnp.sun = (unsigned long)sun; + if (acpi_has_method(dev->handle, "_SUN")) { result = device_create_file(&dev->dev, &dev_attr_sun); if (result) goto end; - } else { - dev->pnp.sun = (unsigned long)-1; } if (acpi_has_method(dev->handle, "_STA")) { -- cgit v1.2.3-58-ga151