path: root/drivers
diff options
authorMika Westerberg <mika.westerberg@linux.intel.com>2018-08-30 11:50:13 +0300
committerWolfram Sang <wsa@the-dreams.de>2018-08-30 22:53:44 +0200
commit7fd6d98b89f382d414e1db528e29a67bbd749457 (patch)
treeb2661725294f667f216e6b45a19175a2572a42b6 /drivers
parent5b394b2ddf0347bef56e50c69a58773c94343ff3 (diff)
i2c: i801: Allow ACPI AML access I/O ports not reserved for SMBus
Commit 7ae81952cda ("i2c: i801: Allow ACPI SystemIO OpRegion to conflict with PCI BAR") made it possible for AML code to access SMBus I/O ports by installing custom SystemIO OpRegion handler and blocking i80i driver access upon first AML read/write to this OpRegion. However, while ThinkPad T560 does have SystemIO OpRegion declared under the SMBus device, it does not access any of the SMBus registers: Device (SMBU) { ... OperationRegion (SMBP, PCI_Config, 0x50, 0x04) Field (SMBP, DWordAcc, NoLock, Preserve) { , 5, TCOB, 11, Offset (0x04) } Name (TCBV, 0x00) Method (TCBS, 0, NotSerialized) { If ((TCBV == 0x00)) { TCBV = (\_SB.PCI0.SMBU.TCOB << 0x05) } Return (TCBV) /* \_SB_.PCI0.SMBU.TCBV */ } OperationRegion (TCBA, SystemIO, TCBS (), 0x10) Field (TCBA, ByteAcc, NoLock, Preserve) { Offset (0x04), , 9, CPSC, 1 } } Problem with the current approach is that it blocks all I/O port access and because this system has touchpad connected to the SMBus controller after first AML access (happens during suspend/resume cycle) the touchpad fails to work anymore. Fix this so that we allow ACPI AML I/O port access if it does not touch the region reserved for the SMBus. Fixes: 7ae81952cda ("i2c: i801: Allow ACPI SystemIO OpRegion to conflict with PCI BAR") Link: https://bugzilla.kernel.org/show_bug.cgi?id=200737 Reported-by: Yussuf Khalil <dev@pp3345.net> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers')
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 941c223f6491..04b60a349d7e 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1415,6 +1415,13 @@ static void i801_add_tco(struct i801_priv *priv)
+static bool i801_acpi_is_smbus_ioport(const struct i801_priv *priv,
+ acpi_physical_address address)
+ return address >= priv->smba &&
+ address <= pci_resource_end(priv->pci_dev, SMBBAR);
static acpi_status
i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
u64 *value, void *handler_context, void *region_context)
@@ -1430,7 +1437,7 @@ i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
- if (!priv->acpi_reserved) {
+ if (!priv->acpi_reserved && i801_acpi_is_smbus_ioport(priv, address)) {
priv->acpi_reserved = true;
dev_warn(&pdev->dev, "BIOS is accessing SMBus registers\n");