lkml.org 
[lkml]   [2009]   [Feb]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2] libata: Don't trust current capacity values in identify words 57-58
    Hello.

    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.
    >
    > While we're at it, clean up this function to use named constants for the
    > identify word values.
    >
    > Signed-off-by: Robert Hancock <hancockrwd@gmail.com>
    >

    Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>

    ... though I'm not sure that the rename should be a part of this patch.

    > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
    > index 9fbf059..33b5549 100644
    > --- a/drivers/ata/libata-core.c
    > +++ b/drivers/ata/libata-core.c
    > @@ -1322,14 +1322,16 @@ static u64 ata_id_n_sectors(const u16 *id)
    > {
    > if (ata_id_has_lba(id)) {
    > if (ata_id_has_lba48(id))
    > - return ata_id_u64(id, 100);
    > + return ata_id_u64(id, ATA_ID_LBA_CAPACITY_2);
    > else
    > - return ata_id_u32(id, 60);
    > + return ata_id_u32(id, ATA_ID_LBA_CAPACITY);
    > } else {
    > if (ata_id_current_chs_valid(id))
    > - return ata_id_u32(id, 57);
    > + return id[ATA_ID_CUR_CYLS] * id[ATA_ID_CUR_HEADS] *
    > + id[ATA_ID_CUR_SECTORS];
    >

    It won't hurt to comment on why the capacity is ignored.
    Unfortunately, the IDE code lacks such comment.

    MBR, Sergei


    --
    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/

    \
     
     \ /
      Last update: 2009-02-18 12:23    [W:0.023 / U:0.528 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site