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@xxxxxxxxxxxxxxx
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> Changes in v2:
> -Modify the value which acpi_gsb_i2c_write_bytes() returns instead of
> checking + modifying the return value in its caller
