Messages in this thread | | | From | Joel Stanley <> | Date | Tue, 18 Sep 2018 10:41:12 +0930 | Subject | Re: [PATCH] i2c: aspeed: Acknowledge most interrupts early in interrupt handler |
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On Fri, 14 Sep 2018 at 13:00, Guenter Roeck <linux@roeck-us.net> 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 <jae.hyun.yoo@linux.intel.com> > Cc: Joel Stanley <joel@jms.id.au> > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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 <joel@jms.id.au>
Cheers,
Joel
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