On 01/17/2013 07:02 AM, Rafael J. Wysocki wrote:
On Wednesday, January 16, 2013 11:15:25 AM Alex Hung wrote:
This is to fix acpica returns an error and terminate AML execution as
soon as BIOS tries to access ACPI's RTC registers.
BugLink: http://launchpad.net/bugs/1065066
Can you please describe the problem in more detail in the changelog itself?
Providing a link to the bug report doesn't explain why you think this fix
is the best possible one. Which quite frankly I'm not sure of.
Hi,
Sure.
It is found that BIOS declared a RTC device with an OperationRegion as
below (1). When the BIOS executes accesses to the registers such as in
Method _Q33 in an EC (2), the kernel outputs messages (3) because there
is no handler for this OperationRegion. The patch is to create a handler
to avoid the errors in AML's execution.
(1)
Device (RTC)
{
Name (_HID, EisaId ("PNP0B00"))
...
OperationRegion (CMS0, SystemCMOS, Zero, 0x40)
Field (CMS0, ByteAcc, NoLock, Preserve)
{
RTSE, 8,
Offset (0x02),
RTMN, 8,
Offset (0x04),
RTHR, 8,
Offset (0x06),
RTDY, 8,
RTDE, 8
}
}
(2)
Method (_Q33, 0, NotSerialized)
{
Store (^^RTC.RTMN, Local0)
FromBCD (Local0, Local0)
Store (^^RTC.RTHR, Local1)
FromBCD (Local1, Local1)
Store (^^RTC.RTDY, Local2)
Store (^^RTC.RTSE, Local3)
...
}
(3)
[ 5553.247507] ACPI Error: No handler for Region [CMS0]
(ffff88023503b2d0) [SystemCMOS] (20121018/evregion-376)
[ 5553.247526] ACPI Error: Region SystemCMOS (ID=5) has no handler
(20121018/exfldio-305)
[ 5553.247545] ACPI Error: Method parse/execution failed
[\_SB_.PCI0.LPCB.EC0_._Q33] (Node ffff8802350609d8), AE_NOT_EXIST
(20121018/psparse-537)
[ 5553.247603] Failed to execute _Q33
Signed-off-by: Alex Hung <alex.hung@xxxxxxxxxxxxx>
---
drivers/acpi/Kconfig | 9 +++
drivers/acpi/Makefile | 1 +
drivers/acpi/acpi_rtc.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 150 insertions(+)
create mode 100644 drivers/acpi/acpi_rtc.c
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 38c5078..fb90397 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -181,6 +181,15 @@ config ACPI_DOCK
This driver supports ACPI-controlled docking stations and removable
drive bays such as the IBM Ultrabay and the Dell Module Bay.
+config ACPI_RTC
+ tristate "RTC"
+ default m
+ help
+ This driver supports an ACPI RTC device. It enables BIOS to read and
+ to write ACPI RTC registers declared in an OperationRegion with
+ RegionSpace as SYSTEMCMOS. This is required if BIOS needs to access
+ RTC registers during run-time such as a number of HP laptops.
+
config ACPI_I2C
def_tristate I2C
depends on I2C
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 2a4502b..383c62b 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_I2C) += acpi_i2c.o
+obj-$(CONFIG_ACPI_RTC) += acpi_rtc.o
# processor has its own "processor." module_param namespace
processor-y := processor_driver.o processor_throttling.o
diff --git a/drivers/acpi/acpi_rtc.c b/drivers/acpi/acpi_rtc.c
new file mode 100644
index 0000000..0ddcfc8
--- /dev/null
+++ b/drivers/acpi/acpi_rtc.c
@@ -0,0 +1,140 @@
+/*
+ * acpi_rtc - ACPI RTC Driver
+ *
+ * Copyright (C) 2013 Alex Hung <alex.hung@xxxxxxxxxxxxx>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+#include <linux/miscdevice.h>
+
+#define pr_fmt(fmt) "acpi_rtc: " fmt
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("acpi*:PNP0B00:*");
+
+static const struct acpi_device_id rtc_device_ids[] = {
+ {"PNP0B00", 0},
+ {"", 0},
+};
+
+static acpi_status acpi_acpi_handle_locate_callback(acpi_handle handle,
+ u32 level, void *context, void **return_value)
+{
+ struct acpi_device *dev = context;
+ dev->handle = handle;
+
+ return AE_CTRL_TERMINATE;
+}
+
+static acpi_status
+acpi_rtc_space_handler(u32 function, acpi_physical_address address,
+ u32 bits, u64 *value64,
+ void *handler_context, void *region_context)
+{
+ return AE_OK;
+}
+
+static int rtc_install_handlers(struct acpi_device *rtc_dev)
+{
+ acpi_status status;
+ status = acpi_install_address_space_handler(rtc_dev->handle,
+ ACPI_ADR_SPACE_CMOS,
+ &acpi_rtc_space_handler,
+ NULL, rtc_dev);
+ if (ACPI_FAILURE(status)) {
+ pr_info("Fail to install ACPI RTC handler\n");
+ return AE_ERROR;
+ }
+
+ return 0;
+}
+
+static int acpi_rtc_add(struct acpi_device *device)
+{
+ int ret;
+ acpi_status status;
+ acpi_handle rtc_dev;
+
+ status = acpi_get_devices(rtc_device_ids[0].id,
+ acpi_acpi_handle_locate_callback,
+ &rtc_dev, &rtc_dev);
+ if (!ACPI_SUCCESS(status))
+ return AE_NOT_FOUND;
+
+ ret = rtc_install_handlers((struct acpi_device *) &rtc_dev);
+
+ return ret;
+}
+
+static int acpi_rtc_remove(struct acpi_device *device, int type)
+{
+ acpi_status status;
+ status = acpi_remove_address_space_handler(device->handle,
+ ACPI_ADR_SPACE_CMOS,
+ &acpi_rtc_space_handler);
+ if (!ACPI_SUCCESS(status))
+ return AE_ERROR;
+
+ return AE_OK;
+}
+
+static struct acpi_driver acpi_rtc_driver = {
+ .name = "rtc",
+ .class = "ACPI_RTC_CLASS",
+ .ids = rtc_device_ids,
+ .ops = {
+ .add = acpi_rtc_add,
+ .remove = acpi_rtc_remove,
+ },
+};
+
+static int __init rtc_init(void)
+{
+ int err;
+
+ pr_info("Initializing ACPI RTC module\n");
+ err = acpi_bus_register_driver(&acpi_rtc_driver);
+ if (err) {
+ pr_err("Unable to register acpi driver.\n");
+ goto error_acpi_register;
+ }
+
+ return 0;
+
+error_acpi_register:
+
+ return err;
+}
+
+static void __exit rtc_exit(void)
+{
+ pr_info("Exiting ACPI RTC module\n");
+ acpi_bus_unregister_driver(&acpi_rtc_driver);
+}
+
+module_init(rtc_init);
+module_exit(rtc_exit);
So all it does is to install an empty address space handler for the CMOS
address space, right?
Bob, I wonder what you think about that?
Rafael
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