[External] Re: [PATCH v2] i2c: aspeed: Fix i2c bus hang in slave read

Jian Zhang zhangjian.3032 at bytedance.com
Fri Sep 29 01:04:23 AEST 2023


> From: "Andi Shyti"<andi.shyti at kernel.org>
> Date:  Thu, Sep 28, 2023, 22:51
> Subject:  [External] Re: [PATCH v2] i2c: aspeed: Fix i2c bus hang in slave read
> To: "Jian Zhang"<zhangjian.3032 at bytedance.com>
> Cc: <brendan.higgins at linux.dev>, <benh at kernel.crashing.org>, <joel at jms.id.au>, <andrew at aj.id.au>, <zhangjian3032 at gmail.com>, <yulei.sh at bytedance.com>, <xiexinnan at bytedance.com>, "Tommy Huang"<tommy_huang at aspeedtech.com>, "Wolfram Sang"<wsa at kernel.org>, "open list:ARM/ASPEED I2C DRIVER"<linux-i2c at vger.kernel.org>, "moderated list:ARM/ASPEED I2C DRIVER"<openbmc at lists.ozlabs.org>, "moderated list:ARM/ASPEED MACHINE SUPPORT"<linux-arm-kernel at lists.infradead.org>, "moderated list:ARM/ASPEED MACHINE SUPPORT"<linux-aspeed at lists.ozlabs.org>, "open list"<linux-kernel at vger.kernel.org>
> Hi Jian,
>
> On Wed, Sep 27, 2023 at 11:42:43PM +0800, Jian Zhang wrote:
> > When the `CONFIG_I2C_SLAVE` option is enabled and the device operates
> > as a slave, a situation arises where the master sends a START signal
> > without the accompanying STOP signal. This action results in a
> > persistent I2C bus timeout. The core issue stems from the fact that
> > the i2c controller remains in a slave read state without a timeout
> > mechanism. As a consequence, the bus perpetually experiences timeouts.
> >
> > In this case, the i2c bus will be reset, but the slave_state reset is
> > missing.
> >
> > Fixes: fee465150b45 ("i2c: aspeed: Reset the i2c controller when timeout occurs")
> > Signed-off-by: Jian Zhang <zhangjian.3032 at bytedance.com>
>
> Why I'm failing to find your v1 patch? And where is the
> changelog?
Sorry, something was missing,
v2:
* remove the i2c slave reset and only move the `bus->slave_state =
ASPEED_I2C_SLAVE_INACTIVE` to the aspeed_i2c_init

[0]: https://lore.kernel.org/linux-arm-kernel/20230810072155.3726352-1-zhangjian.3032@bytedance.com/T/
Jian
>
> Andi


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