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From: Wolfram Sang <wsa@the-dreams.de>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Ulrich Hecht <uli+renesas@fpond.eu>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	linux-serial@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] serial: sh-sci: Fix receive on SCIFA/SCIFB variants with DMA
Date: Fri, 12 Oct 2018 14:19:08 +0200	[thread overview]
Message-ID: <20181012121908.sbwsojs7vvhiztbb@ninjato> (raw)
In-Reply-To: <20181009174158.4476-1-geert+renesas@glider.be>

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On Tue, Oct 09, 2018 at 07:41:58PM +0200, Geert Uytterhoeven wrote:
> On SCIFA and SCIFB serial ports with DMA support (i.e. some ports on
> R-Car Gen2 and RZ/G1 SoCs), receive DMA operations are submitted before
> the DMA channel pointer is initialized.  Hence this fails, and the
> driver tries to fall back to PIO.  However, at this early phase in the
> initialization sequence, fallback to PIO does not work, leading to a
> serial port that cannot receive any data.
> 
> Fix this by calling sci_submit_rx() after initialization of the DMA
> channel pointer.
> 
> Reported-by: Jinzai Solution and RVC Test Teams via Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Brainstorming: keep Shimoda-san's address as is and mention the test
teams in the commit message?

> Fixes: 2c4ee23530ffc022 ("serial: sh-sci: Postpone DMA release when falling back to PIO")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

> ---
> Reported on r8a7790/lager using SCIFA1 on Debug Serial 1.

I hope to test this on Lager this weekend. I am quite sure it will work
now, but then we have this formally checked, too.

> Tested on r8a7791/koelsch using SCIFA3 on EXIO-B.

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  reply	other threads:[~2018-10-12 12:19 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-09 17:41 [PATCH] serial: sh-sci: Fix receive on SCIFA/SCIFB variants with DMA Geert Uytterhoeven
2018-10-12 12:19 ` Wolfram Sang [this message]
2018-10-15 11:49   ` Wolfram Sang

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