Re: [PATCH v2 2/2] i2c: designware: Handle invalid SMBus block data response length value

[Jarkko Nikula]

On 7/26/23 11:00, Tam Nguyen wrote:
> In the I2C_FUNC_SMBUS_BLOCK_DATA case, the invalid length byte value
> (outside of 1-32) of the SMBus block data response from the Slave device
> is not correctly handled by the I2C Designware driver.
>
> In case IC_EMPTYFIFO_HOLD_MASTER_EN==1, which cannot be detected
> from the registers, the Master can be disabled only if the STOP bit
> is set. Without STOP bit set, the Master remains active, holding the bus
> until receiving a block data response length. This hangs the bus and
> is unrecoverable.
>
> Avoid this by issuing another dump read to reach the stop condition when
> an invalid length byte is received.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Tam Nguyen <tamnguyenchi@xxxxxxxxxxxxxxxxxxxxxx>
> ---
>   drivers/i2c/busses/i2c-designware-master.c | 15 +++++++++++++--
>   1 file changed, 13 insertions(+), 2 deletions(-)
Acked-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>