From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Subject: Re: Impact of no_lba48{_dma} = 1 ?
Date: Wed, 07 Feb 2007 17:09:34 +0300
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To: Steven Scholz <steven.scholz@imc-berlin.de>
Cc: Alan <alan@lxorguk.ukuu.org.uk>, linux-ide@vger.kernel.org

Hello.

Steven Scholz wrote:

>>>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?

    If you're asking in general, no, that does not follow from that code.
    It only takes care of the no_lba48_dma case.

MBR, Sergei