From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A9F822DF96; Fri, 25 Apr 2025 06:41:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745563280; cv=none; b=B9LZhPmRMzjeojHWRVFUv3BcVdenayjYT5XRhkZPk6RMnq0BisVK29nb9SRPQxG4eQe49rnc9Bd79dOKF+kneWnFTdP7AG1acEE655WhCrnu/nuX/gzSj1Jh2nzg6/ICj4q7aT2/Y7dAfEK3XNVZGCLKRb/VGPogquvLhKB09DE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745563280; c=relaxed/simple; bh=caqDoDHC4N/BJwCN/vbQlVrvvBBi9e4J4az3N5xkiR8=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=n3V4CcvzLMgNE/62GQcB4ADyEOsZnin302Tc+yY7TS2qcBIT5PFaq1UCPsayc6RgRkepJDBj4dpjjVgG3m53imI1btI9AejFilwHoOe3N+lrz8p/wj8JnvgrJPv1iKEXcMQP4+m49FR1b/obwK0VLBWfqYyzOUhxzsbU2Qaw55s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=syalvRI9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="syalvRI9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D94DC4CEEB; Fri, 25 Apr 2025 06:41:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745563279; bh=caqDoDHC4N/BJwCN/vbQlVrvvBBi9e4J4az3N5xkiR8=; h=Date:Subject:To:References:From:In-Reply-To:From; b=syalvRI92jI128TlTG3R7wRPGu5QOr9AJAV9xqhmx91jNPc1rxepzKb7ljimfFSQn vVhhTA6Plurrw7oRqCoVOA4krUajhFIX9tB0qnl3Dv/uo8/NpN6Ch280TPelYY+Jx+ DcmcYXPWIY2SLx1z9vao5S+DA7tj6fbam0ud+so5N+JAM3qh3LGC64b2iVov2Yr5IY ITbWsBfrnPlxTGKyT3YtTnxmK7GkHARYWXs3fqj7bGxykNjHRBjb+F1zkTztFJY2xk X7xBqeaAUmJ2mfxYI3+ZafU8XmCHrvvPNt9cclxhztlfVvT8Jdh/nQB903FBm4g+qG tN8TsxfR1rK9w== Message-ID: <57d75d55-81e3-445f-a705-e8c116281515@kernel.org> Date: Fri, 25 Apr 2025 08:41:14 +0200 Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 4/4] serial: 8250_dw: fix PSLVERR on RX_TIMEOUT To: Yunhui Cui , arnd@arndb.de, andriy.shevchenko@linux.intel.com, benjamin.larsson@genexis.eu, gregkh@linuxfoundation.org, heikki.krogerus@linux.intel.com, ilpo.jarvinen@linux.intel.com, jkeeping@inmusicbrands.com, john.ogness@linutronix.de, 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 References: <20250425062425.68761-1-cuiyunhui@bytedance.com> <20250425062425.68761-4-cuiyunhui@bytedance.com> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 25. 04. 25, 8:24, Yunhui Cui wrote: > In the case of RX_TIMEOUT, to avoid PSLVERR, disable the FIFO > before reading UART_RX when UART_LSR_DR is not set. > > Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt") > Signed-off-by: Yunhui Cui > --- > drivers/tty/serial/8250/8250_dw.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c > index 07f9be074b4b..1e364280a108 100644 > --- a/drivers/tty/serial/8250/8250_dw.c > +++ b/drivers/tty/serial/8250/8250_dw.c > @@ -273,6 +273,7 @@ static int dw8250_handle_irq(struct uart_port *p) > unsigned int quirks = d->pdata->quirks; > unsigned int status; > unsigned long flags; > + unsigned char old_fcr; No more unsigned char, please. Use u8. > @@ -288,9 +289,19 @@ static int dw8250_handle_irq(struct uart_port *p) > uart_port_lock_irqsave(p, &flags); > status = serial_lsr_in(up); > > - if (!(status & (UART_LSR_DR | UART_LSR_BI))) > + if (!(status & (UART_LSR_DR | UART_LSR_BI))) { > + /* To avoid PSLVERR, disable the FIFO first. */ > + if (up->fcr & UART_FCR_ENABLE_FIFO) { > + old_fcr = serial_in(up, UART_FCR); > + serial_out(up, UART_FCR, old_fcr & ~1); s/1/UART_FCR_ENABLE_FIFO/ > + } > + > (void) p->serial_in(p, UART_RX); > > + if (up->fcr & UART_FCR_ENABLE_FIFO) > + serial_out(up, UART_FCR, old_fcr); > + } > + > uart_port_unlock_irqrestore(p, flags); > } > -- js suse labs