* Jarkko Nikula <jarkko.nikula@xxxxxxxxx> [080930 04:52]: > On Mon, 29 Sep 2008 23:21:00 +0100 > "ext Ben Dooks" <ben-linux@xxxxxxxxx> wrote: > > > On Thu, Sep 25, 2008 at 10:53:47AM +0300, Tony Lindgren wrote: > > > From: Jarkko Nikula <jarkko.nikula@xxxxxxxxx> > > > > > > If there is a signal pending and wait_for_completion_interruptible_timeout > > > terminates with -ERESTARTSYS, we return and disable the i2c clocks in > > > omap_i2c_xfer. > > > > > > If we terminate before sending last i2c message with a stop condition, the > > > bus remains busy and we are not able to send new messages into bus with > > > successive omap_i2c_xfer calls. Therefore a pending signal is not caught > > > here and we return only because of timeout or i2c error. > > > > I assume that this is preferable to aborting an transfer when the > > signal is caught (if possible) ? > > > Most probably yes as long as the stop condition is generated > successfully. IRCC bug behind this fix, OMAP I2C went into bus > arbitration without code able to recover easily or something like that. > > Would it be ok to let this fix as now, probably adding FIXME line near > wait_for_completion_timeout so that we don't break anything now but > note that this is not optimal fix? Here's this one updated with a comment. Tony
>From d93aaaf440acb6705c2eac4fc7ee8c9a4f32580f Mon Sep 17 00:00:00 2001 From: Jarkko Nikula <jarkko.nikula@xxxxxxxxx> Date: Fri, 17 Oct 2008 07:16:49 -0700 Subject: [PATCH] i2c-omap: Do not use interruptible wait call in omap_i2c_xfer_msg If there is a signal pending and wait_for_completion_interruptible_timeout terminates with -ERESTARTSYS, we return and disable the i2c clocks in omap_i2c_xfer. If we terminate before sending last i2c message with a stop condition, the bus remains busy and we are not able to send new messages into bus with successive omap_i2c_xfer calls. Therefore a pending signal is not caught here and we return only because of timeout or i2c error. Signed-off-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxx> Signed-off-by: Juha Yrjola <juha.yrjola@xxxxxxxxxxxxx> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> --- drivers/i2c/busses/i2c-omap.c | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 608038d..17476ec 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -328,8 +328,12 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, w |= OMAP_I2C_CON_STP; omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); - r = wait_for_completion_interruptible_timeout(&dev->cmd_complete, - OMAP_I2C_TIMEOUT); + /* + * REVISIT: We should abort the transfer on signals, but the bus goes + * into arbitration and we're currently unable to recover from it. + */ + r = wait_for_completion_timeout(&dev->cmd_complete, + OMAP_I2C_TIMEOUT); dev->buf_len = 0; if (r < 0) return r; -- 1.5.6.rc3.21.g8c6b5
