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From: Sergei Shtylyov <sshtylyov@mvista.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>,
	Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
	linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/20] ata_piix: unify code for programming PIO and MWDMA timings
Date: Sun, 20 Feb 2011 23:42:48 +0300	[thread overview]
Message-ID: <4D617CC8.3020108@ru.mvista.com> (raw)
In-Reply-To: <20110220185958.364df4cc@lxorguk.ukuu.org.uk>

Hello.

On 20-02-2011 21:59, Alan Cox wrote:

>>> +	if (ata_pio_need_iordy(adev) || use_mwdma)
>>>    		control |= 2;	/* IE enable */

>>      Why IORDY is enabled for MWDMA has always been beyond me... I understand
>> that the stupid Intel docs are to be blamed here.

> I fail to see whats stupid about the docs ?

    Association of IORDY with DMA mode is wrong.

> The same timing register set is used for MWDMA and PIO cycles in MWDMA
> tuned modes (eg ATAPI). Thus the controller needs to be in an MWDMA mode
> whose timings are compatible with the PIO timing and we want IORDY in use
> for the PIO transfer parts.

    Yeah, especially if we also set the bit which only enables fast timing for 
DMA. ;-)
    PIO mode is setup by different code, and it takes care of the IORDY 
setting according to the PIO rules (and it gets called). DMA mode setup should 
just ignore the IORDY setting as in all other sane drivers.

> Alan

WBR, Sergei

  reply	other threads:[~2011-02-20 20:44 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-08 12:23 [PATCHSET] ata: rework support for PIIX-alike PATA controllers Bartlomiej Zolnierkiewicz
2011-02-08 12:23 ` [PATCH 01/20] ata_piix: SITRE handling fix Bartlomiej Zolnierkiewicz
2011-02-08 13:04   ` Alan Cox
2011-02-08 13:02     ` Bartlomiej Zolnierkiewicz
2011-02-08 12:23 ` [PATCH 02/20] ata_piix: unify code for programming PIO and MWDMA timings Bartlomiej Zolnierkiewicz
2011-02-20 13:36   ` Sergei Shtylyov
2011-02-20 18:59     ` Alan Cox
2011-02-20 20:42       ` Sergei Shtylyov [this message]
2011-02-20 21:07         ` Alan Cox
2011-02-21 11:38           ` Sergei Shtylyov
2011-02-21 11:53             ` Sergei Shtylyov
2011-02-21 12:00               ` Alan Cox
2011-02-21 11:58             ` Alan Cox
2011-02-21 11:59               ` Sergei Shtylyov
2011-02-08 12:23 ` [PATCH 03/20] pata_efar: fix register naming used in efar_set_piomode() Bartlomiej Zolnierkiewicz
2011-02-08 12:24 ` [PATCH 04/20] pata_efar: unify code for programming PIO and MWDMA timings Bartlomiej Zolnierkiewicz
2011-02-20 14:32   ` Sergei Shtylyov
2011-02-08 12:24 ` [PATCH 05/20] pata_efar: always program master_data before slave_data Bartlomiej Zolnierkiewicz
2011-02-08 13:07   ` Alan Cox
2011-02-08 13:16     ` Bartlomiej Zolnierkiewicz
2011-02-08 13:25       ` Alan Cox
2011-02-08 13:28         ` Bartlomiej Zolnierkiewicz
2011-02-08 13:39           ` Alan Cox
2011-02-08 13:57             ` Bartlomiej Zolnierkiewicz
2011-02-08 14:12               ` Alan Cox
2011-02-08 14:32                 ` Bartlomiej Zolnierkiewicz
2011-02-08 13:38         ` Sergei Shtylyov
2011-02-19  9:25           ` Bartlomiej Zolnierkiewicz
2011-02-19 16:48             ` Alan Cox
2011-02-20 10:38               ` Bartlomiej Zolnierkiewicz
2011-02-20 11:36                 ` Alan Cox
2011-02-21 20:06             ` Jeff Garzik
2011-02-22  9:19               ` Bartlomiej Zolnierkiewicz
2011-02-22 11:14                 ` Alan Cox
2011-02-23  8:45                   ` Bartlomiej Zolnierkiewicz
2011-02-23  8:53                     ` Bartlomiej Zolnierkiewicz
2011-02-23 10:17                       ` Bartlomiej Zolnierkiewicz
2011-02-23  9:14                     ` Alan Cox
2011-02-23 10:28                       ` Bartlomiej Zolnierkiewicz
2011-02-23 10:36                         ` Alan Cox
2011-02-24 17:53                         ` Alan Cox
2011-02-10 14:23   ` Sergei Shtylyov
2011-02-10 17:14     ` Bartlomiej Zolnierkiewicz
2011-02-10 17:55       ` Sergei Shtylyov
2011-02-08 12:24 ` [PATCH 06/20] pata_it8213: fix register naming used in it8213_set_piomode() Bartlomiej Zolnierkiewicz
2011-02-08 12:24 ` [PATCH 07/20] pata_it8213: unify code for programming PIO and MWDMA timings Bartlomiej Zolnierkiewicz
2011-02-20 14:37   ` Sergei Shtylyov
2011-02-08 12:24 ` [PATCH 08/20] pata_it8213: add UDMA100 and UDMA133 support Bartlomiej Zolnierkiewicz
2011-02-08 12:24 ` [PATCH 09/20] pata_oldpiix: unify code for programming PIO and MWDMA timings Bartlomiej Zolnierkiewicz
2011-02-20 14:52   ` Sergei Shtylyov
2011-02-08 12:24 ` [PATCH 10/20] pata_radisys: " Bartlomiej Zolnierkiewicz
2011-02-20 15:01   ` Sergei Shtylyov
2011-02-08 12:24 ` [PATCH 11/20] pata_rdc: " Bartlomiej Zolnierkiewicz
2011-02-08 12:25 ` [PATCH 12/20] pata_rdc: parallel scanning needs an extra locking Bartlomiej Zolnierkiewicz
2011-02-20 15:04   ` Sergei Shtylyov
2011-02-08 12:25 ` [PATCH 13/20] pata_rdc: add Power Management support Bartlomiej Zolnierkiewicz
2011-02-08 12:25 ` [PATCH 14/20] pata_oldpiix: add locking for parallel scanning Bartlomiej Zolnierkiewicz
2011-02-10 14:28   ` Sergei Shtylyov
2011-02-08 12:25 ` [PATCH 15/20] pata_oldpiix: enable parallel scan Bartlomiej Zolnierkiewicz
2011-02-08 12:25 ` [PATCH 16/20] ata_piix: add EFAR SLC90E66 support Bartlomiej Zolnierkiewicz
2011-02-08 13:13   ` Alan Cox
2011-02-08 13:27     ` Bartlomiej Zolnierkiewicz
2011-02-08 13:38       ` Alan Cox
2011-02-08 14:01         ` Bartlomiej Zolnierkiewicz
2011-02-08 12:25 ` [PATCH 17/20] ata_piix: add IT8213 support Bartlomiej Zolnierkiewicz
2011-02-08 12:25 ` [PATCH 18/20] ata_piix: add RDC support Bartlomiej Zolnierkiewicz
2011-02-08 12:25 ` [PATCH 19/20] ata_piix: add Intel old PIIX support Bartlomiej Zolnierkiewicz
2011-02-08 12:26 ` [PATCH 20/20] ata_piix: add Radisys R82600 support Bartlomiej Zolnierkiewicz

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