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i2c: i801: Allow ACPI AML access I/O ports not reserved for SMBus

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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>
This commit is contained in:
Mika Westerberg 2018-08-30 11:50:13 +03:00 committed by Wolfram Sang
parent 5b394b2ddf
commit 7fd6d98b89
1 changed files with 8 additions and 1 deletions
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9
drivers/i2c/busses/i2c-i801.c
View File

@ -1415,6 +1415,13 @@ static void i801_add_tco(struct i801_priv *priv)
}
#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)
@ -1430,7 +1437,7 @@ i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
*/
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");