Messages in this thread | | | Date | Mon, 16 Feb 2009 18:01:06 -0500 | From | Mark Lord <> | Subject | Re: [PATCH] libata: Don't trust current capacity values in identify words 57-58 |
| |
Robert Hancock wrote: > Hanno Böck reported a problem where an old Conner CP30254 240MB hard drive > was reported as 1.1TB in capacity by libata: > > http://lkml.org/lkml/2009/2/13/134 > > This was caused by libata trusting the drive's reported current capacity in > sectors in identify words 57 and 58 if the drive does not support LBA and the > current CHS translation values appear valid. Unfortunately it seems older > ATA specs were vague about what this field should contain and a number of drives > used values with wrong byte order or that were totally bogus. There's no > unique information that it conveys and so we can just calculate the number > of sectors from the reported current CHS values. > > Signed-off-by: Robert Hancock <hancockrwd@gmail.com> .. > } else { > if (ata_id_current_chs_valid(id)) > - return ata_id_u32(id, 57); > + return id[54] * id[55] * id[56]; > else > return id[1] * id[3] * id[6]; ..
NAK. That's not quite correct, either.
The LBA capacity can be larger than the CHS capacity, so we have to use the reported LBA values if at all possible.
That's why ata_id_is_lba_capacity_ok() exists, and why it looks so peculiar.
Some of those early drives really did require that kind of logic.
Cheers
-- 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/
| |