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From: Steven Scholz <steven.scholz@imc-berlin.de>
To: Alan <alan@lxorguk.ukuu.org.uk>
Cc: linux-ide@vger.kernel.org
Subject: Re: Impact of no_lba48{_dma} = 1 ?
Date: Wed, 07 Feb 2007 14:57:27 +0100	[thread overview]
Message-ID: <45C9DAC7.10701@imc-berlin.de> (raw)
In-Reply-To: <20070207135309.66942d25@localhost.localdomain>

Alan,

>>> Only relevant for DMA really
>> So rqsize is only needed for DMA accesses?
> 
> PIO transfers are sector at a time, or multi-sector up to a usual limit
> of about 16 sectors.

So again: rqsize does not matter for PIO transfer?

Looking at the lines

	if (hwif->no_lba48_dma && lba48 && dma) {
		if (block + rq->nr_sectors > 1ULL << 28)
			dma = 0;
		else
			lba48 = 0;
	}

in drivers/ide/ide-disk.c. Does that mean that 48bit LBA adressing using the
task_ioreg_t stuff is only used for sector numbers larger 1 << 28?
Thus for small HDDs only LBA28 ist used by

			hwif->OUTB(block, IDE_SECTOR_REG);
			hwif->OUTB(block>>=8, IDE_LCYL_REG);
			hwif->OUTB(block>>=8, IDE_HCYL_REG);

???

Thanks a million!!!!

Steven

  parent reply	other threads:[~2007-02-07 13:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-07  9:56 Impact of no_lba48{_dma} = 1 ? Steven Scholz
2007-02-07 11:58 ` Alan
2007-02-07 13:25   ` Steven Scholz
2007-02-07 13:53     ` Alan
2007-02-07 13:49       ` Sergei Shtylyov
2007-02-07 14:11         ` Alan
2007-02-07 14:03           ` Steven Scholz
2007-02-07 14:19             ` Alan
2007-02-07 14:10           ` Sergei Shtylyov
2007-02-07 13:57       ` Steven Scholz [this message]
2007-02-07 14:09         ` Sergei Shtylyov
2007-02-07 14:16         ` Alan

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