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Date: Tue, 20 Oct 2009 16:11:49 -0700
From: "Darrick J. Wong" <djwong@...ibm.com>
To: crane.cai@....com, lenb@...nel.org
Cc: linux-kernel <linux-kernel@...r.kernel.org>,
linux-i2c@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: [PATCH] i2c-scmi: Quirk to work on IBM machines with broken BIOSes
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. It also omits the leading "_" in the method names (it should
be _SBR, not SBR_). Modify the ACPI device scan code to insert the missing HID
if it finds an IBM system with such an object, and modify the i2c-scmi driver
to handle the odd method names.
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@...ibm.com>
---
drivers/acpi/scan.c | 38 ++++++++++++++++++++++++++++++++
drivers/i2c/busses/i2c-scmi.c | 49 ++++++++++++++++++++++++++++++++---------
include/acpi/acpi_drivers.h | 1 +
3 files changed, 77 insertions(+), 11 deletions(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 14a7481..58cb324 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -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>
@@ -1014,6 +1015,41 @@ 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 probe_ibm_smbus_device(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;
@@ -1064,6 +1100,8 @@ 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 (!probe_ibm_smbus_device(device))
+ acpi_add_id(device, ACPI_SMBUS_HID);
break;
case ACPI_BUS_TYPE_POWER:
diff --git a/drivers/i2c/busses/i2c-scmi.c b/drivers/i2c/busses/i2c-scmi.c
index b4a55d4..f0ad03d 100644
--- a/drivers/i2c/busses/i2c-scmi.c
+++ b/drivers/i2c/busses/i2c-scmi.c
@@ -33,6 +33,7 @@ struct acpi_smbus_cmi {
u8 cap_info:1;
u8 cap_read:1;
u8 cap_write:1;
+ struct smbus_methods_t methods;
};
static const struct smbus_methods_t smbus_methods = {
@@ -41,8 +42,15 @@ static const struct smbus_methods_t smbus_methods = {
.mt_sbw = "_SBW",
};
+/* Some IBM BIOSes omit the leading underscore */
+static const struct smbus_methods_t ibm_smbus_methods = {
+ .mt_info = "SBI_",
+ .mt_sbr = "SBR_",
+ .mt_sbw = "SBW_",
+};
+
static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
- {"SMBUS01", 0},
+ {ACPI_SMBUS_HID, 0},
{"", 0}
};
@@ -150,11 +158,11 @@ acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
if (read_write == I2C_SMBUS_READ) {
protocol |= ACPI_SMBUS_PRTCL_READ;
- method = smbus_methods.mt_sbr;
+ method = smbus_cmi->methods.mt_sbr;
input.count = 3;
} else {
protocol |= ACPI_SMBUS_PRTCL_WRITE;
- method = smbus_methods.mt_sbw;
+ method = smbus_cmi->methods.mt_sbw;
input.count = 5;
}
@@ -283,20 +291,21 @@ static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
};
-static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
- const char *name)
+static int acpi_smbus_cmi_probe_cap(struct acpi_smbus_cmi *smbus_cmi,
+ const char *name,
+ const struct smbus_methods_t *methods)
{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
acpi_status status;
- if (!strcmp(name, smbus_methods.mt_info)) {
+ if (!strcmp(name, methods->mt_info)) {
status = acpi_evaluate_object(smbus_cmi->handle,
- smbus_methods.mt_info,
+ methods->mt_info,
NULL, &buffer);
if (ACPI_FAILURE(status)) {
ACPI_ERROR((AE_INFO, "Evaluating %s: %i",
- smbus_methods.mt_info, status));
+ methods->mt_info, status));
return -EIO;
}
@@ -319,17 +328,35 @@ static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
kfree(buffer.pointer);
smbus_cmi->cap_info = 1;
- } else if (!strcmp(name, smbus_methods.mt_sbr))
+ smbus_cmi->methods.mt_info = methods->mt_info;
+ } else if (!strcmp(name, methods->mt_sbr)) {
smbus_cmi->cap_read = 1;
- else if (!strcmp(name, smbus_methods.mt_sbw))
+ smbus_cmi->methods.mt_sbr = methods->mt_sbr;
+ } else if (!strcmp(name, methods->mt_sbw)) {
smbus_cmi->cap_write = 1;
- else
+ smbus_cmi->methods.mt_sbw = methods->mt_sbw;
+ } else {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported CMI method: %s\n",
name));
+ return -ENODEV;
+ }
return 0;
}
+static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
+ const char *name)
+{
+ int res;
+
+ res = acpi_smbus_cmi_probe_cap(smbus_cmi, name, &smbus_methods);
+ if (!res)
+ return 0;
+
+ res = acpi_smbus_cmi_probe_cap(smbus_cmi, name, &ibm_smbus_methods);
+ return res;
+}
+
static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
void *context, void **return_value)
{
diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index f4906f6..c724a08 100644
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -65,6 +65,7 @@
#define ACPI_VIDEO_HID "LNXVIDEO"
#define ACPI_BAY_HID "LNXIOBAY"
#define ACPI_DOCK_HID "LNXDOCK"
+#define ACPI_SMBUS_HID "SMBUS01"
/*
* For fixed hardware buttons, we fabricate acpi_devices with HID
--
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