linux-kernel - Re: [PATCH] mmc: block: disable the reliable write If the card does not support CMD23

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Date:	Wed, 26 Aug 2015 15:20:11 +0800
From:	Shawn Lin <shawn.lin@...k-chips.com>
To:	LIYONG <sdliyong@...il.com>, Ulf Hansson <ulf.hansson@...aro.org>
Cc:	shawn.lin@...k-chips.com, Chris Ball <chris@...ntf.net>,
	linux-mmc <linux-mmc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mmc: block: disable the reliable write If the card does
 not support CMD23

On 2015/8/26 14:15, LIYONG wrote:
> Hi Uffe,
>
> The bool variable do_rel_wr is used on line 1408 and line 1436:
> if (brq->data.blocks> 1 || do_rel_wr) {
> 		/* SPI multiblock writes terminate using a special
> 		 * token, not a STOP_TRANSMISSION request.
> 		 */
>
> 	if (do_rel_wr)
> 		mmc_apply_rel_rw(brq, card, req);
>
> If a card does not support CMD23, I think we need to set the do_rel_wr to false at the beginning of this mmc_blk_rw_rq_prep function

Hi Yong,

You miss the point, Ulf means you should remove
"(do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23)" as well.

No need to check card->quirks & MMC_QUIRK_BLK_NO_CMD23 twice, you have 
did it while checking do_rel_wr, right?

bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
(req->cmd_flags & REQ_META)) &&
(rq_data_dir(req) == WRITE) &&
- (md->flags & MMC_BLK_REL_WR);
+ (md->flags & MMC_BLK_REL_WR) &&
+ !(card->quirks & MMC_QUIRK_BLK_NO_CMD23);

>
> Thanks,
> Yong Li
> ----------------------------------------
>> Date: Tue, 25 Aug 2015 14:06:43 +0200
>> Subject: Re: [PATCH] mmc: block: disable the reliable write If the card does not support CMD23
>> From: ulf.hansson@...aro.org
>> To: sdliyong@...il.com
>> CC: chris@...ntf.net; linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org
>>
>> On 14 August 2015 at 09:30, <sdliyong@...il.com> wrote:
>>> From: Yong Li <sdliyong@...il.com>
>>>
>>> Signed-off-by: Yong Li <sdliyong@...il.com>
>>> ---
>>> drivers/mmc/card/block.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>> index 452782b..d9e3c45 100644
>>> --- a/drivers/mmc/card/block.c
>>> +++ b/drivers/mmc/card/block.c
>>> @@ -1366,7 +1366,8 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>>> bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
>>> (req->cmd_flags & REQ_META)) &&
>>> (rq_data_dir(req) == WRITE) &&
>>> - (md->flags & MMC_BLK_REL_WR);
>>> + (md->flags & MMC_BLK_REL_WR) &&
>>> + !(card->quirks & MMC_QUIRK_BLK_NO_CMD23);
>>
>> Further down in mmc_blk_rw_rq_prep() we check for
>> MMC_QUIRK_BLK_NO_CMD23. That check becomes redundant after this
>> change, please remove that check as a part of this patch as well.
>>
>>>
>>> memset(brq, 0, sizeof(struct mmc_blk_request));
>>> brq->mrq.cmd = &brq->cmd;
>>> --
>>> 2.1.0
>>>
>>
>> Kind regards
>> Uffe
>   		 	   		  --
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>
>


-- 
Best Regards
Shawn Lin

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