* [Query]: What should we do in txd->tx_submit() and device_issue_pending()
@ 2011-07-19 8:29 viresh kumar
2011-07-19 8:49 ` Koul, Vinod
0 siblings, 1 reply; 3+ messages in thread
From: viresh kumar @ 2011-07-19 8:29 UTC (permalink / raw)
To: Koul, Vinod, Dan Williams
Cc: linux-kernel@vger.kernel.org, Shiraz HASHIM, Armando VISCONTI
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?
--
viresh
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [Query]: What should we do in txd->tx_submit() and device_issue_pending()
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
0 siblings, 1 reply; 3+ messages in thread
From: Koul, Vinod @ 2011-07-19 8:49 UTC (permalink / raw)
To: viresh kumar, Williams, Dan J
Cc: linux-kernel@vger.kernel.org, Shiraz HASHIM, Armando VISCONTI
(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)
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
~Vinod
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Query]: What should we do in txd->tx_submit() and device_issue_pending()
2011-07-19 8:49 ` Koul, Vinod
@ 2011-07-19 9:08 ` viresh kumar
0 siblings, 0 replies; 3+ messages in thread
From: viresh kumar @ 2011-07-19 9:08 UTC (permalink / raw)
To: Koul, Vinod
Cc: Williams, Dan J, linux-kernel@vger.kernel.org, Shiraz HASHIM,
Armando VISCONTI
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
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-07-19 9:09 UTC | newest]
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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
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