>>>
>> BUG_ON line is not part of this change. It was already there in existing
>> driver.
>> Based on log, I see DMA transfer is done for 224 bytes followed by 1
>> successful PIO transfer and then on next PIO transfer it received packet
>> xfer complete interrupt with incomplete transfer bytes and that where it hit
>> BUG_ON condition.
>>
>>
>
> Yes, that BUG_ON is caused by the DMA transferring. Everything works fine be
> setting dma=false in the code, hence it's likely not a bug in the code (at
> least for now it looks fine), but likely that HW is not programmed correctly.
>
> It works with this change:
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index fe5b89abc576..8e059e94b94e 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -1170,10 +1170,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev
> *i2c_dev,
> time_left, completion_done(&i2c_dev->msg_complete),
> i2c_dev->msg_err);
>
> + tegra_i2c_init(i2c_dev, true);
> +
> if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
> return 0;
>
> - tegra_i2c_init(i2c_dev, true);
> /* start recovery upon arbitration loss in single master mode */
> if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) {
> if (!i2c_dev->is_multimaster_mode)
>
>
> Which means that HW state is kept dirty after DMA transfer. Please check
> everything carefully.
FIFO trigger levels are diff for PIO Vs DMA so it need to be moved to xfer
function. Will fix that.
