Re: [PATCH 1/2] serial: imx: remove the DMA wait queue

From: Huang Shijie
Date: Fri May 30 2014 - 06:23:10 EST


On Fri, May 30, 2014 at 09:27:20AM +0000, Wang, Jiada (ESD) wrote:
> Hi Shijie
>
> After apply this patch into our kernel,
> We are facing data hang issue when sending big size file (2M used in test) to uart port
> Note: Rx port is also keep receiving data.
>
> After read the implementation of uart_stop(),
> I feel like, stop_tx() is used to perform flow control when like a XOFF is received.
> Which means no data should be dropped, as they may need to be sent out,
> When next start_tx() is called.
>
> But by calling dmaengine_termiate_all(), the data already be submitted to DMA engine,
> May be lost, thus cause data hang.
>
> What do you think?
This patch has been reverted by Greg.

I also noticed the data loss issue.

thanks
Huang Shijie
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