Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1416712

Re: [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA

Show all headers | View raw

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

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA Charanya Venkatraman <charanya@codeaurora.org> - 2016-06-07 12:30 +0200
  Re: [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA Stephen Boyd <sboyd@codeaurora.org> - 2016-06-08 01:10 +0200
  Re: [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA Andy Gross <andy.gross@linaro.org> - 2016-06-09 21:30 +0200

csiph-web