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From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
	"wsa+renesas@sang-engineering.com"
	<wsa+renesas@sang-engineering.com>,
	"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>
Subject: RE: [PATCH v2 2/2] mmc: renesas_sdhi: use multiple segments if possible
Date: Wed, 22 May 2019 05:11:28 +0000
Message-ID: <OSAPR01MB30898CAE4DDD98EDBF479BCCD8000@OSAPR01MB3089.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <20190521215702.GA15483@kunai>

Hi Wolfram-san,

> From: Wolfram Sang, Sent: Wednesday, May 22, 2019 6:57 AM
> 
> Hi Shimoda-san,
> 
> > > > > +	if (host->pdev->dev.iommu_group &&
> > > >
> > > > I wonder if I am too cautious, but maybe we should have another
> > > > condition here to be checked first, namely "host->mmc->max_segs < 512"?
> > >
> > > I got it. I'll fix it on v3 patch.
> >
> > I'm afraid but I misunderstood this condition is
> > "host->pdata->max_segs", not "host->mmc->max_segs", to avoid small
> > max_segs value than pdata->max_segs?
> 
> You are right. I was in deed thinking mmc->max_segs because it will be
> set at probe time, so it would work with values > 512. But I missed the
> case you described, I am sorry. But using pdata->max_segs should work.

Thank you for the reply. I got it!

> > (No one has such max_segs value at the moment though.)
> 
> Yes. I want to be future-proof here. Just to avoid that the value might
> be "magically" decreased if the value might be bigger than 512. It would
> be hard to find then because it is kinda deep in the driver.

I got it.

> Two more remarks:
> 
> * We should probably use a define for the magic value 512.

I think so. I also would like to use a define for a magic value 32.

> * Maybe you could add a comment to the init_card function describing why
>   we can increase max_segs in that case. Basically, a short summary of
>   your patch description.

It's a good idea! I'll add such a short summary.

> Does this make sense to you?

Yes. Thank you for your comments. I'll make v3 patch later.

Best regards,
Yoshihiro Shimoda

> Kind regards,
> 
>    Wolfram


      reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13  4:29 [PATCH v2 0/2] mmc: renesas_sdhi: improve performance by using IOMMU Yoshihiro Shimoda
2019-05-13  4:29 ` [PATCH v2 1/2] mmc: tmio: No memory size limitation if runs on IOMMU Yoshihiro Shimoda
2019-05-13  4:29 ` [PATCH v2 2/2] mmc: renesas_sdhi: use multiple segments if possible Yoshihiro Shimoda
2019-05-13  9:00   ` Wolfram Sang
2019-05-13  9:46     ` Yoshihiro Shimoda
2019-05-13 11:34       ` Yoshihiro Shimoda
2019-05-13 13:54         ` Wolfram Sang
2019-05-14  6:05       ` Yoshihiro Shimoda
2019-05-21 21:57         ` Wolfram Sang
2019-05-22  5:11           ` Yoshihiro Shimoda [this message]

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