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acpi: Support IBM SMBus CMI devices

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On some old IBM workstations and desktop computers, the BIOS presents in the
DSDT an SMBus object that is missing the HID identifier that the i2c-scmi
driver looks for.  Modify the ACPI device scan code to insert the missing HID
if it finds an IBM system with such an object.

Affected machines: IntelliStation Z20/Z30.  Note that the i2c-i801 driver no
longer works on these machines because of ACPI resource conflicts.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Darrick J. Wong 2010-03-24 14:38:37 +01:00 committed by Jean Delvare
parent ae6be51ed0
commit 222e82ac9f
2 changed files with 40 additions and 0 deletions
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38
drivers/acpi/scan.c
View file

@ -8,6 +8,7 @@
#include <linux/acpi.h>
#include <linux/signal.h>
#include <linux/kthread.h>
#include <linux/dmi.h>
#include <acpi/acpi_drivers.h>
@ -1032,6 +1033,41 @@ static void acpi_add_id(struct acpi_device *device, const char *dev_id)
list_add_tail(&id->list, &device->pnp.ids);
}
/*
* Old IBM workstations have a DSDT bug wherein the SMBus object
* lacks the SMBUS01 HID and the methods do not have the necessary "_"
* prefix. Work around this.
*/
static int acpi_ibm_smbus_match(struct acpi_device *device)
{
acpi_handle h_dummy;
struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
int result;
if (!dmi_name_in_vendors("IBM"))
return -ENODEV;
/* Look for SMBS object */
result = acpi_get_name(device->handle, ACPI_SINGLE_NAME, &path);
if (result)
return result;
if (strcmp("SMBS", path.pointer)) {
result = -ENODEV;
goto out;
}
/* Does it have the necessary (but misnamed) methods? */
result = -ENODEV;
if (ACPI_SUCCESS(acpi_get_handle(device->handle, "SBI", &h_dummy)) &&
ACPI_SUCCESS(acpi_get_handle(device->handle, "SBR", &h_dummy)) &&
ACPI_SUCCESS(acpi_get_handle(device->handle, "SBW", &h_dummy)))
result = 0;
out:
kfree(path.pointer);
return result;
}
static void acpi_device_set_id(struct acpi_device *device)
{
acpi_status status;
@ -1082,6 +1118,8 @@ static void acpi_device_set_id(struct acpi_device *device)
acpi_add_id(device, ACPI_BAY_HID);
else if (ACPI_SUCCESS(acpi_dock_match(device)))
acpi_add_id(device, ACPI_DOCK_HID);
else if (!acpi_ibm_smbus_match(device))
acpi_add_id(device, ACPI_SMBUS_IBM_HID);
break;
case ACPI_BUS_TYPE_POWER:

2
include/acpi/acpi_drivers.h
View file

@ -65,6 +65,8 @@
#define ACPI_VIDEO_HID "LNXVIDEO"
#define ACPI_BAY_HID "LNXIOBAY"
#define ACPI_DOCK_HID "LNXDOCK"
/* Quirk for broken IBM BIOSes */
#define ACPI_SMBUS_IBM_HID "SMBUSIBM"
/*
* For fixed hardware buttons, we fabricate acpi_devices with HID