4.18-stable review patch. If anyone has any objections, please let me know.
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From: Hans de Goede hdegoede@redhat.com
commit c463a158cb6c5d9a85b7d894cd4f8116e8bd6be0 upstream.
acpi_gsb_i2c_write_bytes() returns i2c_transfer()'s return value, which is the number of transfers executed on success, so 1.
The ACPI code expects us to store 0 in gsb->status for success, not 1.
Specifically this breaks the following code in the Thinkpad 8 DSDT:
ECWR = I2CW = ECWR /* _SB_.I2C1.BAT0.ECWR */ If ((ECST == Zero)) { ECRD = I2CR /* _SB_.I2C1.I2CR */ }
Before this commit we set ECST to 1, causing the read to never happen breaking battery monitoring on the Thinkpad 8.
This commit makes acpi_gsb_i2c_write_bytes() return 0 when i2c_transfer() returns 1, so the single write transfer completed successfully, and makes it return -EIO on for other (unexpected) return values >= 0.
Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede hdegoede@redhat.com Acked-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Wolfram Sang wsa@the-dreams.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/i2c/i2c-core-acpi.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/drivers/i2c/i2c-core-acpi.c +++ b/drivers/i2c/i2c-core-acpi.c @@ -482,11 +482,16 @@ static int acpi_gsb_i2c_write_bytes(stru msgs[0].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); - if (ret < 0) - dev_err(&client->adapter->dev, "i2c write failed\n");
kfree(buffer); - return ret; + + if (ret < 0) { + dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret); + return ret; + } + + /* 1 transfer must have completed successfully */ + return (ret == 1) ? 0 : -EIO; }
static acpi_status