On Wed, Feb 14, 2018 at 09:29:52AM -0600, Ben Gardner wrote:
> One I2C bus on my Atom E3845 board has been broken since 4.9.
> It has two devices, both declared by ACPI and with built-in drivers.
> 
> There are two back-to-back transactions originating from the kernel, one
> targeting each device. The first transaction works, the second one locks
> up the I2C controller. The controller never recovers.
> 
> These kernel logs show up whenever an I2C transaction is attempted after
> this failure.
> i2c-designware-pci 0000:00:18.3: timeout in disabling adapter
> i2c-designware-pci 0000:00:18.3: timeout waiting for bus ready
> 
> Waiting for the I2C controller status to indicate that it is enabled
> before programming it fixes the issue.
> 
> I have tested this patch on 4.14 and 4.15.
> 
> Fixes: commit 2702ea7dbec5 ("i2c: designware: wait for disable/enable only if necessary")
> Cc: linux-stable <stable@vger.kernel.org> #4.13+
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Signed-off-by: Ben Gardner <gardner.ben@gmail.com>

Applied to for-current, thanks!