From mboxrd@z Thu Jan  1 00:00:00 1970
From: Steven Scholz <steven.scholz@imc-berlin.de>
Subject: Re: Impact of no_lba48{_dma} = 1 ?
Date: Wed, 07 Feb 2007 14:57:27 +0100
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To: Alan <alan@lxorguk.ukuu.org.uk>
Cc: linux-ide@vger.kernel.org

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