On Fri, Jun 14, 2013 at 04:37:41PM +0200, Wolfram Sang wrote: > On Fri, Jun 07, 2013 at 10:51:23AM +0200, Christian Ruppert wrote: > > The designware block is not always properly disabled in the case of > > transfer errors. Interrupts from aborted transfers might be handled > > after the data structures for the following transfer are initialised but > > before the hardware is set up. This can corrupt the data structures to > > the point that the system is stuck in an infinite interrupt loop (where > > FIFOs are never emptied because dev->msg_read_idx == dev->msgs_num). > > > > This patch cleanly disables the designware-i2c hardware at the end of > > every transfer, be it successful or not. > > > > This patch requires https://patchwork.kernel.org/patch/2601241/ to be > > applied first. > > These last two lines should be below "---". > > > > > Signed-off-by: Christian Ruppert <christian.rupp...@abilis.com> > > --- > > drivers/i2c/busses/i2c-designware-core.c | 10 ++++++++-- > > 1 files changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-designware-core.c > > b/drivers/i2c/busses/i2c-designware-core.c > > index b75d292..55a9991 100644 > > --- a/drivers/i2c/busses/i2c-designware-core.c > > +++ b/drivers/i2c/busses/i2c-designware-core.c > > @@ -588,11 +588,19 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg > > msgs[], int num) > > ret = wait_for_completion_timeout(&dev->cmd_complete, HZ); > > if (ret == 0) { > > dev_err(dev->dev, "controller timed out\n"); > > + /* i2c_dw_init implicitly disables the adapter */ > > i2c_dw_init(dev); > > ret = -ETIMEDOUT; > > goto done; > > } > > > > + /* > > + * We must disable the adapter before unlocking the &dev->lock mutex > > + * below. Otherwise the hardware might continue generating interrupts > > + * which in turn causes a race condition with the following transfer. > > I added "Needs some more investigation if the additional interrupts are > a hardware bug or this driver doesn't handle them correctly yet." to the > comment and > > Applied to for-next, thanks!
Sorry for the late response (was on vacation). This patch looks good to me as well. Thanks for applying it! -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
