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

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From: Huang Shijie <b32955@freescale.com>
To: "Wang, Jiada (ESD)" <Jiada_Wang@mentor.com>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	"Behme, Dirk - Bosch" <dirk.behme@de.bosch.com>
Subject: Re: [PATCH 1/2] serial: imx: remove the DMA wait queue
Date: Fri, 30 May 2014 17:01:30 +0800	[thread overview]
Message-ID: <20140530090128.GA4380@shlinux1.ap.freescale.net> (raw)
In-Reply-To: <857E9EDCA6C0904DB3357321AA9123EBE14B5A2C@NA-MBX-03.mgc.mentorg.com>

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

WARNING: multiple messages have this Message-ID (diff)

From: b32955@freescale.com (Huang Shijie)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] serial: imx: remove the DMA wait queue
Date: Fri, 30 May 2014 17:01:30 +0800	[thread overview]
Message-ID: <20140530090128.GA4380@shlinux1.ap.freescale.net> (raw)
In-Reply-To: <857E9EDCA6C0904DB3357321AA9123EBE14B5A2C@NA-MBX-03.mgc.mentorg.com>

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

next prev parent reply	other threads:[~2014-05-30 10:23 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-23  4:32 [PATCH 1/2] serial: imx: remove the DMA wait queue Huang Shijie
2014-05-23  4:32 ` Huang Shijie
2014-05-23  4:32 ` Huang Shijie
2014-05-23  4:32 ` [PATCH 2/2] serial: imx: disable the receiver ready interrupt for imx_stop_rx Huang Shijie
2014-05-23  4:32   ` Huang Shijie
2014-05-23  4:32   ` Huang Shijie
2014-05-23  6:10   ` Dirk Behme
2014-05-23  6:10     ` Dirk Behme
2014-05-23  8:04     ` Huang Shijie
2014-05-23  8:04       ` Huang Shijie
2014-05-30  5:52   ` Dirk Behme
2014-05-30  5:52     ` Dirk Behme
2014-05-30  4:53     ` Huang Shijie
2014-05-30  4:53       ` Huang Shijie
2014-05-30  4:53       ` Huang Shijie
2014-05-23  4:40 ` [PATCH 1/2 rebased] serial: imx: remove the DMA wait queue Huang Shijie
2014-05-23  4:40   ` Huang Shijie
2014-05-23  4:40   ` Huang Shijie
2014-05-30  9:27 ` [PATCH 1/2] " Wang, Jiada (ESD)
2014-05-30  9:27   ` Wang, Jiada (ESD)
2014-05-30  9:01   ` Huang Shijie [this message]
2014-05-30  9:01     ` Huang Shijie

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