lkml.org 
[lkml]   [2018]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 215/217] i2c: core: ACPI: Properly set status byte to 0 for multi-byte writes
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    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
    @@ -475,11 +475,16 @@ 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

    \
     
     \ /
      Last update: 2018-08-23 11:17    [W:2.941 / U:0.048 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site