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 --- Changes in v2: -Modify the value which acpi_gsb_i2c_write_bytes() returns instead of checking + modifying the return value in its caller --- drivers/i2c/i2c-core-acpi.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c index 7c3b4740b94b..b8f303dea305 100644 --- 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(struct i2c_client *client, 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
On 2018-08-12 12:53, Hans de Goede wrote:
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.
I'm wondering if this might be fallout from one of 35cd67a0caf7 ("i2c: viperboard: return message count on master_xfer success") de9a8634f1cb ("i2c: pmcmsp: return message count on master_xfer success")
But I have no idea what i2c driver these Thinkpads are using, so it is not unlikely that I'm way off...
Cheers, Peter
Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede hdegoede@redhat.com
Changes in v2: -Modify the value which acpi_gsb_i2c_write_bytes() returns instead of checking + modifying the return value in its caller
Hi,
On 12-08-18 22:39, Peter Rosin wrote:
On 2018-08-12 12:53, Hans de Goede wrote:
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.
I'm wondering if this might be fallout from one of 35cd67a0caf7 ("i2c: viperboard: return message count on master_xfer success") de9a8634f1cb ("i2c: pmcmsp: return message count on master_xfer success")
No, these are using the designware driver, so these commits are not the cause, this simply is a long standing bug.
Regards,
Hans
On Sun, Aug 12, 2018 at 12:53:20PM +0200, Hans de Goede wrote:
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
On Sun, Aug 12, 2018 at 12:53:20PM +0200, Hans de Goede wrote:
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
Applied to for-next, thanks!
linux-stable-mirror@lists.linaro.org
-
Hans de Goede -
Mika Westerberg -
Peter Rosin -
Wolfram Sang