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From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Peter Rosin <peda@axentia.se>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>,
	Josh Wu <rainyfeeling@outlook.com>,
	Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
	linux-kernel@vger.kernel.org,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Marek Vasut <marek.vasut@gmail.com>,
	linux-mtd@lists.infradead.org,
	Richard Weinberger <richard@nod.at>,
	Brian Norris <computersforpeace@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] mtd: nand: raw: atmel: add module param to avoid using dma
Date: Tue, 3 Apr 2018 09:18:43 +0200	[thread overview]
Message-ID: <20180403071843.GI14180@piout.net> (raw)
In-Reply-To: <8e35701f-1bfa-c9c0-62e6-48ed19d7ba37@axentia.se>

On 02/04/2018 at 22:23:17 +0200, Peter Rosin wrote:
> >> No, but did it again and checked, see transcript below.
> > 
> > I don't use devmem2. Is 'readback' information accurate or is it
> > always what's been written? Because when you write 0x33 to 0xFFFFECBC,
> > 0x33 is read back, but just after that, when you read it again it's 0.
> 
> Looking at the devmem2 source, it seems very likely that the compiler
> optimizes out the read and thus outputs what has been written.
> 

At least on x86, it is not optimized out.


-- 
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

  parent reply	other threads:[~2018-04-03  7:18 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-29 13:10 [PATCH] mtd: nand: raw: atmel: add module param to avoid using dma Peter Rosin
2018-03-29 13:33 ` Boris Brezillon
2018-03-29 13:37   ` Peter Rosin
2018-03-29 13:44     ` Boris Brezillon
2018-03-29 14:27       ` Peter Rosin
2018-03-30 21:43         ` Peter Rosin
2018-04-02 12:22         ` Boris Brezillon
2018-04-02 17:59           ` Peter Rosin
2018-04-02 19:28             ` Boris Brezillon
2018-04-02 20:20               ` Boris Brezillon
2018-04-02 20:32                 ` Boris Brezillon
2018-04-03  6:11                 ` Peter Rosin
2018-04-03  7:18                   ` Boris Brezillon
2018-04-11 14:44                     ` Peter Rosin
2018-04-11 14:59                       ` Boris Brezillon
2018-04-11 15:10                         ` Peter Rosin
2018-04-11 15:34                           ` Boris Brezillon
2018-04-11 15:34                       ` Nicolas Ferre
2018-04-12  7:18                         ` Peter Rosin
2018-05-22 18:03                         ` Peter Rosin
2018-05-23 10:42                           ` Boris Brezillon
2018-05-25 14:51                         ` Tudor Ambarus
2018-05-26 17:40                           ` Peter Rosin
2018-05-27  9:18                           ` Peter Rosin
2018-05-27 22:11                             ` Peter Rosin
2018-05-28 10:10                               ` Peter Rosin
2018-05-28 14:27                                 ` Boris Brezillon
2018-05-28 15:52                                   ` Peter Rosin
2018-05-28 16:09                                     ` Boris Brezillon
2018-05-28 16:09                                     ` Nicolas Ferre
2018-05-29  6:30                                 ` Eugen Hristev
2018-05-29  7:10                                   ` Peter Rosin
2018-05-29  7:25                                     ` Eugen Hristev
2018-05-29 14:49                                   ` Boris Brezillon
2018-05-29 15:01                                     ` Eugen Hristev
2018-05-29 15:15                                       ` Boris Brezillon
2018-05-29 15:21                                         ` Eugen Hristev
2018-05-29 15:46                                           ` Boris Brezillon
2018-05-29 17:57                                             ` Boris Brezillon
2018-05-29 21:37                                               ` Peter Rosin
2018-06-04 15:46                                 ` Tudor Ambarus
2018-06-04 16:03                                   ` Boris Brezillon
2018-04-03  6:51                 ` Peter Rosin
2018-04-03  7:15                   ` Boris Brezillon
2018-04-03  7:32                     ` Boris Brezillon
2018-04-03  8:14                     ` Peter Rosin
2018-04-03  8:30                       ` Boris Brezillon
2018-04-02 20:23               ` Peter Rosin
2018-04-02 20:35                 ` Boris Brezillon
2018-04-03  7:18                 ` Alexandre Belloni [this message]
2018-04-03  8:37                   ` Peter Rosin
2018-03-29 14:20 ` Nicolas Ferre
2018-03-29 14:23   ` Peter Rosin
2018-03-29 14:29   ` Boris Brezillon
2018-06-18  8:39 ` Boris Brezillon
2018-06-18 14:00   ` Miquel Raynal
2018-06-25 12:31   ` Miquel Raynal

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