RE: [PATCH V8 3/5] i2c: tegra: Add DMA Support

[Sowjanya Komatineni]

> >>  drivers/i2c/busses/Kconfig     |   2 +-
> >>  drivers/i2c/busses/i2c-tegra.c | 362 
> >> ++++++++++++++++++++++++++++++++++++++---
> >>  2 files changed, 339 insertions(+), 25 deletions(-)
> > 
> > Tegra20 crashes because of this patch:
> > 
> [snip]
> > <4>[    3.395915] ------------[ cut here ]------------
> > <2>[    3.395919] kernel BUG at drivers/i2c/busses/i2c-tegra.c:810!
> The BUG line is from:
>
>       if (status & I2C_INT_PACKET_XFER_COMPLETE) {
>               if (i2c_dev->is_curr_dma_xfer)
>                       i2c_dev->msg_buf_remaining = 0;
>               BUG_ON(i2c_dev->msg_buf_remaining);
>               complete(&i2c_dev->msg_complete);
>       }
>
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.