From: Wolfram Sang <wsa@kernel.org>
To: Tam Nguyen <tamnguyenchi@os.amperecomputing.com>
Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
patches@amperecomputing.com, jarkko.nikula@linux.intel.com,
andriy.shevchenko@linux.intel.com,
mika.westerberg@linux.intel.com, jsd@semihalf.com,
chuong@os.amperecomputing.com, darren@os.amperecomputing.com,
stable@vger.kernel.org
Subject: Re: [PATCH v2] i2c: designware: Disable TX_EMPTY irq while waiting for block length byte
Date: Wed, 8 Nov 2023 10:20:04 +0100 [thread overview]
Message-ID: <ZUtSxNviS1w+yVYV@ninjato> (raw)
In-Reply-To: <20231102033009.4555-1-tamnguyenchi@os.amperecomputing.com>
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On Thu, Nov 02, 2023 at 10:30:08AM +0700, Tam Nguyen wrote:
> During SMBus block data read process, we have seen high interrupt rate
> because of TX_EMPTY irq status while waiting for block length byte (the
> first data byte after the address phase). The interrupt handler does not
> do anything because the internal state is kept as STATUS_WRITE_IN_PROGRESS.
> Hence, we should disable TX_EMPTY IRQ until I2C DesignWare receives
> first data byte from I2C device, then re-enable it to resume SMBus
> transaction.
>
> It takes 0.789 ms for host to receive data length from slave.
> Without the patch, i2c_dw_isr() is called 99 times by TX_EMPTY interrupt.
> And it is none after applying the patch.
>
> Cc: stable@vger.kernel.org
> Co-developed-by: Chuong Tran <chuong@os.amperecomputing.com>
> Signed-off-by: Chuong Tran <chuong@os.amperecomputing.com>
> Signed-off-by: Tam Nguyen <tamnguyenchi@os.amperecomputing.com>
Applied to for-current, thanks!
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prev parent reply other threads:[~2023-11-08 9:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-02 3:30 [PATCH v2] i2c: designware: Disable TX_EMPTY irq while waiting for block length byte Tam Nguyen
2023-11-03 12:59 ` Jarkko Nikula
2023-11-03 13:02 ` Serge Semin
2023-11-08 9:20 ` Wolfram Sang [this message]
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