On 05/02/2018 12:48 AM, Baolin Wang wrote: > On 2 May 2018 at 13:23, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote: >> >>>> We should maybe handle this in the core somewhen, though. Or? >>> >>> Thanks. Yes, It will more helpful if we can handle this in the i2c core. >> >> To understand the issue better: which kind of devices in your system >> still send I2C transfers when the system is going to suspend? Do you >> know? > > Now we found the touch screen device will trigger I2C transfers when > the system is going to suspend. > And you have to fix it (touch screen) - not your i2c driver. Otherwise, you can get situation when set of I2C transfers (executed from some kthread/work/threaded_irq/..) will be just interrupted in the middle - usual behavior after this is (I2C timeout) [and/or not-functional I2C client device [and/or I2C bus stuck (worst case)]. In case, somebody is trying to access I2C after .suspend_noirq() stage I2C bus driver should produce big fat warning and, most probably, abort suspend. Above, in general, can be part of I2C core functionality. -- regards, -grygorii
