From: Stephen Boyd <sboyd@codeaurora.org>
To: Charanya Venkatraman <charanya@codeaurora.org>
Cc: agross@codeaurora.org, david.brown@linaro.org,
andy.gross@linaro.org, gregkh@linuxfoundation.org,
jslaby@suse.com, linux-soc@vger.kernel.org,
linux-serial@vger.kernel.org, sricharan@codeaurora.org,
architt@codeaurora.org, linux-arm-msm@vger.kernel.org,
ntelkar@codeaurora.org, galak@codeaurora.org,
linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, absahu@codeaurora.org,
njaigane@codeaurora.org
Subject: Re: [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA
Date: Tue, 7 Jun 2016 16:08:44 -0700 [thread overview]
Message-ID: <20160607230844.GA28218@codeaurora.org> (raw)
In-Reply-To: <1465295321-10506-1-git-send-email-charanya@codeaurora.org>
On 06/07, Charanya Venkatraman wrote:
> Avoid data corruption issues that result in CRC errors during file
> transfers over serial ports at higher baud rates.
>
> The current msm_serial driver masks the FIFO Rx interrupts in
> msm_start_rx_dma() since Rx FIFO interrupts are not required in DMA
> mode. However, msm_complete_rx_dma() re-enables the Rx FIFO interrupts
> which could cause RXSTALE event to be processed when a TXLEV interrupt
> occurs.
>
> The following is the sequence of events that could occur resulting in
> data corruption.
>
> msm_start_rx_dma -> msm_complete_rx_dma -->
> spin_unlock_irqrestore(&port->lock) -->
> msm_uart_irq()(For TXLEV interrupt) --> msm_handle_rx_dm() (Read from
> FIFO resulting in data corruption)
>
> The patch fixes the issue by not restoring the RXLEV and RXSTALE
> interrupts in msm_complete_rx_dma(). These interrupts are required only
> in FIFO mode.
>
> Signed-off-by: Charanya Venkatraman <charanya@codeaurora.org>
> ---
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2016-06-07 23:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1462896580-11554-1>
2016-06-03 11:10 ` [PATCH v2] tty:serial:msm:Do not restore Rx interrupts in DMA Charanya Venkatraman
2016-06-03 15:47 ` Greg KH
2016-06-07 10:28 ` [PATCH v3] " Charanya Venkatraman
2016-06-07 23:08 ` Stephen Boyd [this message]
2016-06-09 19:27 ` Andy Gross
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