From: viresh kumar <viresh.kumar@st.com>
To: "Koul, Vinod" <vinod.koul@intel.com>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Shiraz HASHIM <shiraz.hashim@st.com>,
Armando VISCONTI <armando.visconti@st.com>
Subject: Re: [Query]: What should we do in txd->tx_submit() and device_issue_pending()
Date: Tue, 19 Jul 2011 14:38:42 +0530 [thread overview]
Message-ID: <4E25499A.9070703@st.com> (raw)
In-Reply-To: <438BB0150E931F4B9CE701519A4463010871D6C2EF@bgsmsx502.gar.corp.intel.com>
On 07/19/2011 02:19 PM, Koul, Vinod wrote:
> (pls wrap your email to 80lines, I have reflowed below for readability)
>> Hi Dan/Vinod,
>>
>> I have one query regarding implementation of few routines in DMA drivers.
>>
>> What the exact purpose of txd->tx_submit() and device_issue_pending() routines?
>>
>> Should tx_submit() always start physical transfer (Obviously, if channel is
>> free)? Or should it just queue requests and then finally a call to
>> device_issue_pending() must start physical transfers?
> (reflowed your email for 80lines)
Sorry!! :(
> tx_submit is not supposed to start the transfer, it is supposed to add the
> descriptors in dma driver's queue. The issue_pending is supposed to actually
> start the transfer. The reasons were well articulated is discussion we had
> when we did the DMA documentation.
> Pls see https://lkml.org/lkml/2011/5/24/530
>
Thanks.
--
viresh
prev parent reply other threads:[~2011-07-19 9:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-19 8:29 [Query]: What should we do in txd->tx_submit() and device_issue_pending() viresh kumar
2011-07-19 8:49 ` Koul, Vinod
2011-07-19 9:08 ` viresh kumar [this message]
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