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SubjectRe: [PATCH] ide-cd: handle fragmented packet commands gracefully
Date
On Sunday 21 June 2009 10:55:27 Borislav Petkov wrote:
> There are some devices in the wild that clear the DRQ bit during the
> last word of a packet command and therefore could use a "second chance"
> for that last word of data to be xferred instead of simply failing the
> request. Do that by attempting to suck in those last bytes in PIO mode.
>
> In addition, the ATA_ERR bit has to be cleared for we cannot be sure the
> data is valid otherwise.
>
> See http://bugzilla.kernel.org/show_bug.cgi?id=13399 for details.
>
> Signed-off-by: Borislav Petkov <petkovbb@gmail.com>

Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

> ---
> drivers/ide/ide-cd.c | 14 ++++++++++++--
> 1 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
> index 4a19686..8d3f7d0 100644
> --- a/drivers/ide/ide-cd.c
> +++ b/drivers/ide/ide-cd.c
> @@ -592,9 +592,19 @@ static ide_startstop_t cdrom_newpc_intr(ide_drive_t *drive)
> }
> } else if (!blk_pc_request(rq)) {
> ide_cd_request_sense_fixup(drive, cmd);
> - /* complain if we still have data left to transfer */
> +
> uptodate = cmd->nleft ? 0 : 1;
> - if (uptodate == 0)
> +
> + /*
> + * suck out the remaining bytes from the drive in an
> + * attempt to complete the data xfer. (see BZ#13399)
> + */
> + if (!(stat & ATA_ERR) && !uptodate && thislen) {
> + ide_pio_bytes(drive, cmd, write, thislen);
> + uptodate = cmd->nleft ? 0 : 1;
> + }
> +
> + if (!uptodate)
> rq->cmd_flags |= REQ_FAILED;
> }
> goto out_end;


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