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

Sowjanya Komatineni
2019-01-31T16:56:56Z

> >> 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.