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From: Wolfram Sang <wsa@the-dreams.de>
To: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Jun Gao <jun.gao@mediatek.com>,
	Ryder Lee <ryder.lee@mediatek.com>,
	linux-i2c@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-kernel@vger.kernel.org, qii.wang@mediatek.com
Subject: Re: [PATCH] i2c: mediatek: modify threshold passed to i2c_get_dma_safe_msg_buf()
Date: Fri, 8 Mar 2019 15:52:03 +0100	[thread overview]
Message-ID: <20190308145203.GA4743@kunai> (raw)
In-Reply-To: <CAJMQK-j9b3o+KQfN8nLXGiP+TXi8i77=yTTQsEARa6cotPhxzw@mail.gmail.com>

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> > I just checked this issue again and concluded that both are reasonable,
> > the suggestion from me below with the adapter quirk AND your original
> > patch setting the threshold to 1. With my suggestion the core will
> > prevent 0-length messages. But still, we should set the threshold to 1
> > because 0 is a value the HW is not capable of.
> >
> I think quirk might be better, since mediatek said they might have some ICs
> that can handle zero-length transfer in the future, so flags might be
> more clear if they want to restore functionality.

But I guess you don't want to do the zero-length transfer with DMA then?
With that in mind, raising the threshold still makes sense to me.


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WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa@the-dreams.de>
To: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Ryder Lee <ryder.lee@mediatek.com>,
	qii.wang@mediatek.com, Jun Gao <jun.gao@mediatek.com>,
	linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-i2c@vger.kernel.org,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] i2c: mediatek: modify threshold passed to i2c_get_dma_safe_msg_buf()
Date: Fri, 8 Mar 2019 15:52:03 +0100	[thread overview]
Message-ID: <20190308145203.GA4743@kunai> (raw)
In-Reply-To: <CAJMQK-j9b3o+KQfN8nLXGiP+TXi8i77=yTTQsEARa6cotPhxzw@mail.gmail.com>


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> > I just checked this issue again and concluded that both are reasonable,
> > the suggestion from me below with the adapter quirk AND your original
> > patch setting the threshold to 1. With my suggestion the core will
> > prevent 0-length messages. But still, we should set the threshold to 1
> > because 0 is a value the HW is not capable of.
> >
> I think quirk might be better, since mediatek said they might have some ICs
> that can handle zero-length transfer in the future, so flags might be
> more clear if they want to restore functionality.

But I guess you don't want to do the zero-length transfer with DMA then?
With that in mind, raising the threshold still makes sense to me.


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  reply	other threads:[~2019-03-08 14:52 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-15  9:02 [PATCH] i2c: mediatek: modify threshold passed to i2c_get_dma_safe_msg_buf() Hsin-Yi Wang
2019-02-15  9:02 ` Hsin-Yi Wang
2019-02-15  9:09 ` Wolfram Sang
2019-02-15  9:09   ` Wolfram Sang
2019-02-15  9:17   ` Hsin-Yi Wang
2019-02-15  9:17     ` Hsin-Yi Wang
2019-02-15  9:25     ` Wolfram Sang
2019-02-15  9:25       ` Wolfram Sang
2019-02-15 16:36       ` Wolfram Sang
2019-02-15 16:36         ` Wolfram Sang
2019-02-22  6:04         ` Hsin-Yi Wang
2019-02-22  6:04           ` Hsin-Yi Wang
2019-03-08 11:29           ` Wolfram Sang
2019-03-08 11:29             ` Wolfram Sang
2019-03-08 14:39             ` Hsin-Yi Wang
2019-03-08 14:39               ` Hsin-Yi Wang
2019-03-08 14:52               ` Wolfram Sang [this message]
2019-03-08 14:52                 ` Wolfram Sang
2019-03-08 16:22                 ` Hsin-Yi Wang
2019-03-08 16:22                   ` Hsin-Yi Wang
2019-03-09  9:42 ` Wolfram Sang
2019-03-09  9:42   ` Wolfram Sang

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