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.ruppert@xxxxxxxxxx> > --- > 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! BTW since I am currently here: i2c-designware-core should be in the 'algos' directory, no?
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