linux-kernel - Re: [External] Re: [PATCH] i2c: aspeed: change debug level in irq handler

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Message-ID: <7b1f0f17-197d-4c57-b1d2-a9d8ec6ff398@molgen.mpg.de>
Date: Tue, 24 Jun 2025 14:27:52 +0200
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Zhang Jian <zhangjian.3032@...edance.com>
Cc: Ryan Chen <ryan_chen@...eedtech.com>,
 Benjamin Herrenschmidt <benh@...nel.crashing.org>,
 Joel Stanley <joel@....id.au>, Andi Shyti <andi.shyti@...nel.org>,
 Andrew Jeffery <andrew@...econstruct.com.au>, linux-i2c@...r.kernel.org,
 openbmc@...ts.ozlabs.org, linux-arm-kernel@...ts.infradead.org,
 linux-aspeed@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [External] Re: [PATCH] i2c: aspeed: change debug level in irq
 handler

Dear Jian,


Am 24.06.25 um 12:32 schrieb Zhang Jian:

> Thanks for your reply and sorry for the late reply, I was trying to
> figure out why this log occurred, it's quite hard to reproduce.

Thank you for your reply. So few days and over the weekend classifies as 
instant reply. ;-)

Were you able to find a reproducer, or just rebooting?

> I traced all the master and slave states, and eventually found that 
> the behavior matches the description in commit b4cc1cbba519. The
> issue has already been fixed in that commit it was caused by a state
> machine bug that led to the interrupt not being handled correctly.
> 
> see: https://github.com/torvalds/linux/commit/b4cc1cbba519

The commit you found is present in Linux since v6.7-rc7.

> (The state transitions between the master and slave here rely on
> interrupts. When the signal waveform is incomplete (such as during
> power off/on), it may cause state errors or brief unresponsiveness,
> resulting in some log prints.)

Thank you for getting to the bottom of this.

Now that you ran into this, and have a suggestion, how the logging or 
log messages could be improved, please share.


Kind regards,

Paul