On Fri, 14 Sep 2018 at 13:00, Guenter Roeck <[email protected]> wrote: > > Commit 3e9efc3299dd ("i2c: aspeed: Handle master/slave combined irq events > properly") moved interrupt acknowledgment to the end of the interrupt > handler. In part this was done because the AST2500 datasheet says: > > I2CD10 Interrupt Status Register > bit 2 Receive Done Interrupt status > S/W needs to clear this status bit to allow next data receiving. > > Acknowledging Receive Done before receive data was handled resulted in > receive errors on high speed I2C busses. > > However, interrupt acknowledgment was not only moved to the end of the > interrupt handler for Receive Done Interrupt status, but for all interrupt > status bits. This could result in race conditions if a second interrupt was > received during interrupt handling and not handled but still acknowledged > at the end of the interrupt handler. > > Acknowledge only "Receive Done Interrupt status" late in the interrupt > handler to solve the problem. > > Fixes: 3e9efc3299dd ("i2c: aspeed: Handle master/slave combined irq events > properly") > Cc: Jae Hyun Yoo <[email protected]> > Cc: Joel Stanley <[email protected]> > Signed-off-by: Guenter Roeck <[email protected]>
Thanks for getting to the bottom of this Guenter. I gave it a spin on Romulus (ast2500) and Palmetto (ast2400) without issue. Tested-by: Joel Stanley <[email protected]> Cheers, Joel
