Messages in this thread | | | Date | Fri, 4 Apr 2003 16:40:44 +0200 | From | Andries Brouwer <> | Subject | Re: [PATCH] only use 48-bit lba when necessary |
| |
On Fri, Apr 04, 2003 at 02:29:36PM +0200, Jens Axboe wrote:
> 48-bit lba has a non-significant overhead (twice the outb's, 12 instead
s/non-// ?
> of 6 per command), so it makes sense to use 28-bit lba commands whenever > we can. >
> + if (drive->addressing == 1 && block > 0xfffffff) > + lba48 = 1;
Hmm. I wonder whether we should be more cautious, and ask for lba48 as soon as some part of the interval is past this limit. (say, block+nsectors > 0xfffffff)
I don't know whether the standard spells out what happens at the boundary, but for example the LBA low/mid/high, DEV is required to contain the sector number at the place the error occurred, and that is possible only if one stays below the 28-byte sector limit.
Andries
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |