From: John Ogness <john.ogness@linutronix.de>
To: Yunhui Cui <cuiyunhui@bytedance.com>,
arnd@arndb.de, andriy.shevchenko@linux.intel.com,
benjamin.larsson@genexis.eu, cuiyunhui@bytedance.com,
gregkh@linuxfoundation.org, heikki.krogerus@linux.intel.com,
ilpo.jarvinen@linux.intel.com, jirislaby@kernel.org,
jkeeping@inmusicbrands.com, linux-kernel@vger.kernel.org,
linux-serial@vger.kernel.org, markus.mayer@linaro.org,
matt.porter@linaro.org, namcao@linutronix.de, paulmck@kernel.org,
pmladek@suse.com, schnelle@linux.ibm.com,
sunilvl@ventanamicro.com, tim.kryger@linaro.org
Subject: Re: [PATCH v9 3/4] serial: 8250: avoid potential PSLVERR issue
Date: Fri, 20 Jun 2025 13:26:34 +0206 [thread overview]
Message-ID: <848qlmk6bh.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <20250610092135.28738-4-cuiyunhui@bytedance.com>
On 2025-06-10, Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> When the PSLVERR_RESP_EN parameter is set to 1, reading UART_RX while
> the FIFO is enabled and UART_LSR_DR is not set will generate a PSLVERR
> error.
>
> Failure to check the UART_LSR_DR before reading UART_RX, or the non-
> atomic nature of clearing the FIFO and reading UART_RX, poses
> potential risks that could lead to PSLVERR.
>
> PSLVERR is addressed through two methods. One is to introduce
> serial8250_discard_data() to check whether UART_LSR_DR is set before
> reading UART_RX, thus solving the PSLVERR issue when the FIFO is
> enabled. The other is to place FIFO clearing and reading of UART_RX
> under port->lock.
>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
next prev parent reply other threads:[~2025-06-20 11:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-10 9:21 [PATCH v9 0/4] Serial: 8250: Fix PSLVERR related issues Yunhui Cui
2025-06-10 9:21 ` [PATCH v9 1/4] serial: 8250: fix panic due to PSLVERR Yunhui Cui
2025-06-20 11:19 ` John Ogness
2025-07-17 12:19 ` [External] " yunhui cui
2025-07-17 12:32 ` Greg KH
2025-06-10 9:21 ` [PATCH v9 2/4] serial: 8250_dw: fix PSLVERR on RX_TIMEOUT Yunhui Cui
2025-06-23 6:50 ` yunhui cui
2025-06-23 8:32 ` John Ogness
2025-07-11 2:19 ` [External] " yunhui cui
2025-07-17 14:14 ` John Ogness
2025-07-18 15:20 ` Doug Anderson
2025-06-10 9:21 ` [PATCH v9 3/4] serial: 8250: avoid potential PSLVERR issue Yunhui Cui
2025-06-20 11:20 ` John Ogness [this message]
2025-06-10 9:21 ` [PATCH v9 4/4] serial: 8250_dw: assert port->lock is held in dw8250_force_idle() Yunhui Cui
2025-06-20 12:14 ` John Ogness
2025-06-23 6:44 ` [External] " yunhui cui
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