4.4-stable review patch. If anyone has any objections, please let me know.
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From: Mika Westerberg mika.westerberg@linux.intel.com
[ Upstream commit 7fd6d98b89f382d414e1db528e29a67bbd749457 ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/i2c/busses/i2c-i801.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -1272,6 +1272,13 @@ static void i801_add_tco(struct i801_pri }
#ifdef CONFIG_ACPI +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) @@ -1287,7 +1294,7 @@ i801_acpi_io_handler(u32 function, acpi_ */ mutex_lock(&priv->acpi_lock);
- 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");