Re: [PATCH] mmc: dw_mmc: Support predefined multiple block transfers.

Jaehoon Chung
2011-10-05T08:20:03Z

On 10/05/2011 05:02 PM, Seungwon Jeon wrote:

> Jaehoon Chung wrote:
>>
>> Hi Mr.Jeon
>>
>> One question...if we used predefined transfer, didn't send stop-command?
>> then i think that didn't need to enter this condition..how about this?
>>
>> In __dw_mci_start_reqeust() function(at your patch)
>>
>> if (mrq->stop)
>> host->stop_cmdr = dw_mci_prepare_command(slot->mmc, mrq->stop);
>>
>> If i misunderstood something, plz let me know...Thanks.
> Yes, predefined transfer doesn't send stop command normally.
> But if transfer error is occurred, stop command is required.

Thanks for your answer. i didn't look in detail.
your patch is worked when there is data->error, send stop command..right?

This patch looks good to me.

Best Regards,
Jaehoon Chung

>
> Thank you for test.
> Best regards,
> Seungwon Jeon.
>>
>> Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
>>
>> On 09/28/2011 05:23 PM, Seungwon Jeon wrote:
>>
>>> Andrei Warkentin wrote:
>>>> 2011/9/26 Seungwon Jeon <tgih.jun@samsung.com>:
>>>>> Andrei Warkentin wrote:
>>>>>> Hi Seungwon,
>>>>>>
>>>>>> ----- Original Message -----
>>>>>>> From: "Seungwon Jeon" <tgih.jun@samsung.com>
>>>>>>> To: linux-mmc@vger.kernel.org
>>>>>>> Cc: "Chris Ball" <cjb@laptop.org>, linux-samsung-soc@vger.kernel.org,
>>>>>> "kgene kim" <kgene.kim@samsung.com>, "dh han"
>>>>>>> <dh.han@samsung.com>, "Seungwon Jeon" <tgih.jun@samsung.com>
>>>>>>> Sent: Monday, September 26, 2011 7:46:59 AM
>>>>>>> Subject: [PATCH] mmc: dw_mmc: Support predefined multiple block
>>>>>> transfers.
>>>>>>>
>>>>>>> This patch adds the support for predefined multiple block read/write.
>>>>>>>
>>>>>>> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
>>>>>>
>>>>>> Without knowing much about dw_mmc host, your logic otherwise looks ok,
>>>>>> given what
>>>>>> I've previously done for SDHCI as far as CMD23/Auto-CMD23 enhancement.
>>>>>> Just curious, what eMMC cards did you test this on, and what
>>>> improvement
>>>>>> did you see?
>>>>>
>>>>> Thank you for review.
>>>>> As you done, predefined transfer is required for reliable writes and
>>>> eMMC4.5 feature.
>>>>> Sadly, I didn't gain an improvement in my case.
>>>>> (I don't know whether I can clarify the tested eMMC card, just one
>>>> sample.)
>>>>>
>>>>
>>>> So far I've seen some Sandisk cards have a noticeable real-life
>>>> improvement (30%) over
>>>> open-ended transfers.
>>>>
>>>> You might wish to try out https://github.com/andreiw/superalign to be
>>>> certain.
>>>
>>> I had already tested this patch with IOZONE, but I found no difference.
>>> Maybe a result depends on eMMC device.
>>> As your recommend, I applied above benchmark tool.
>>> Predefined transfer seems like a little better, but there is no
>> difference.
>>>
>>> Thanks.
>>> Seungwon Jeon.
>>>
>>>>
>>>> A
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>>
>>
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