On Friday 29 June 2012 03:25 AM, Kevin Hilman wrote: > Hi Shubhrajyoti, > > Shubhrajyoti Datta <omaplinuxkernel@xxxxxxxxx> writes: > >> Hi Kevin, >> Thanks for the patch , >> a doubt below > Thanks for the review. > >> On Wed, Jun 27, 2012 at 7:15 AM, Kevin Hilman <khilman@xxxxxx> wrote: >>> In omap_i2c_xfer(), ensure pm_runtime_put() is called, even on >>> failure. >> So the failure means that the usecount is incremented. However the >> device was not >> enabled. > Correct. > >> In that case could we consider >> >> void pm_runtime_put_noidle(struct device *dev); >> - decrement the device's usage counter >> >> Which will only decrement the counter and does not try to disable it. > No, that is not needed. > >> However I am not sure what happens if you try to disable an already >> disabled device. > The runtime PM core already knows that the device is not enabled so will > not need to call the disable hooks. It already needs this functionality > to support the _get_noresume() and _put_noidle() calls. > > I tested this on 3730/OveroSTORM where I was seeing this i2c xfer > failure (and thus a failure in MMC suspend, which uses I2C to control > the regulator.) > > Hope that helps clarify, Thanks a lot for the clarification. > If so, Wolfram, can you queue this up in your i2c-embedded/for-next > branch since this problem was introduced there. > > Thanks, > > Kevin > >>> Without this, after a failed xfer, the runtime PM usecount will have >>> been incremented, but not decremented >> Agree. >> >>> causing the usecount to never >>> reach zero after a failure. This keeps the device always runtime PM >>> enabled which keeps the enclosing power domain active, and prevents >>> full-chip retention/off from happening during idle. Reviewed-by: Shubhrajyoti D <shubhrajyoti@xxxxxx> >>> Cc: Shubhrajyoti D <shubhrajyoti@xxxxxx> >>> Signed-off-by: Kevin Hilman <khilman@xxxxxx> >>> --- >>> This patch applies to current i2c-embedded/for-next branch >>> >>> drivers/i2c/busses/i2c-omap.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c >>> index 9895fa7..b105733 100644 >>> --- a/drivers/i2c/busses/i2c-omap.c >>> +++ b/drivers/i2c/busses/i2c-omap.c >>> @@ -582,7 +582,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) >>> >>> r = pm_runtime_get_sync(dev->dev); >>> if (IS_ERR_VALUE(r)) >>> - return r; >>> + goto out; >>> >>> r = omap_i2c_wait_for_bb(dev); >>> if (r < 0) >>> -- >>> 1.7.9.2 >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-omap" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-omap" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
