From 70dd6beac02f43a5099fcf5fddf68cfee0cbf479 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 27 May 2010 19:58:37 +0200 Subject: [PATCH] hwmon: (asus_atk0110) Don't load if ACPI resources aren't enforced When the user passes the kernel parameter acpi_enforce_resources=lax, the ACPI resources are no longer protected, so a native driver can make use of them. In that case, we do not want the asus_atk0110 to be loaded. Unfortunately, this driver loads automatically due to its MODULE_DEVICE_TABLE, so the user ends up with two drivers loaded for the same device - this is bad. So I suggest that we prevent the asus_atk0110 driver from loading if acpi_enforce_resources=lax. Signed-off-by: Jean Delvare Acked-by: Luca Tettamanti Cc: Len Brown --- drivers/acpi/osl.c | 9 +++++++++ drivers/hwmon/asus_atk0110.c | 7 +++++++ include/linux/acpi.h | 2 ++ 3 files changed, 18 insertions(+) diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 4bc1c4178f5..78418ce4fc7 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -1206,6 +1206,15 @@ int acpi_check_mem_region(resource_size_t start, resource_size_t n, } EXPORT_SYMBOL(acpi_check_mem_region); +/* + * Let drivers know whether the resource checks are effective + */ +int acpi_resources_are_enforced(void) +{ + return acpi_enforce_resources == ENFORCE_RESOURCES_STRICT; +} +EXPORT_SYMBOL(acpi_resources_are_enforced); + /* * Acquire a spinlock. * diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c index 16c42024072..653db1bda93 100644 --- a/drivers/hwmon/asus_atk0110.c +++ b/drivers/hwmon/asus_atk0110.c @@ -1411,6 +1411,13 @@ static int __init atk0110_init(void) { int ret; + /* Make sure it's safe to access the device through ACPI */ + if (!acpi_resources_are_enforced()) { + pr_err("atk: Resources not safely usable due to " + "acpi_enforce_resources kernel parameter\n"); + return -EBUSY; + } + ret = acpi_bus_register_driver(&atk_driver); if (ret) pr_info("atk: acpi_bus_register_driver failed: %d\n", ret); diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 3da73f5f0ae..2c60f1f70b3 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -248,6 +248,8 @@ int acpi_check_region(resource_size_t start, resource_size_t n, int acpi_check_mem_region(resource_size_t start, resource_size_t n, const char *name); +int acpi_resources_are_enforced(void); + #ifdef CONFIG_PM_SLEEP void __init acpi_no_s4_hw_signature(void); void __init acpi_old_suspend_ordering(void); -- 2.41.0