On Thu, Oct 14, 2010 at 2:53 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> ATA devices don't send D2H Reg FIS after an successful ATA PIO data-in
> command. The host is supposed to take the E_Status of the preceding
> PIO Setup FIS. Update ahci_qc_fill_rtf() such that it takes E_Status
> after a successful ATA PIO data-in command.
>
> Without this patch, result_tf for such a command is filled with the
> content of the previous D2H Reg FIS which belongs to a previous
> command, which can make the command incorrectly seen as failed.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Reported-by: Mark Lord <kernel@xxxxxxxxxxxx>
> Cc: Robert Hancock <hancockrwd@xxxxxxxxx>
> Cc: stable@xxxxxxxxxx
> ---
> drivers/ata/ahci.h | 1 +
> drivers/ata/libahci.c | 17 ++++++++++++++---
> 2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
> index e5fdeeb..d1a0f5b 100644
> --- a/drivers/ata/ahci.h
> +++ b/drivers/ata/ahci.h
> @@ -72,6 +72,7 @@ enum {
> AHCI_CMD_RESET = (1 << 8),
> AHCI_CMD_CLR_BUSY = (1 << 10),
>
> + RX_FIS_PIO_SETUP = 0x20, /* offset of PIO Setup FIS data */
> RX_FIS_D2H_REG = 0x40, /* offset of D2H Register FIS data */
> RX_FIS_SDB = 0x58, /* offset of SDB FIS data */
> RX_FIS_UNK = 0x60, /* offset of Unknown FIS data */
> diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
> index 8eea309..0c482a0 100644
> --- a/drivers/ata/libahci.c
> +++ b/drivers/ata/libahci.c
> @@ -1830,12 +1830,23 @@ static unsigned int ahci_qc_issue(struct ata_queued_cmd *qc)
> static bool ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
> {
> struct ahci_port_priv *pp = qc->ap->private_data;
> - u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
> + u8 *rx_fis = pp->rx_fis;
>
> if (pp->fbs_enabled)
> - d2h_fis += qc->dev->link->pmp * AHCI_RX_FIS_SZ;
> + rx_fis += qc->dev->link->pmp * AHCI_RX_FIS_SZ;
> +
> + /*
> + * After a successful execution of an ATA PIO data-in command,
> + * the device doesn't send D2H Reg FIS to update the TF and
> + * the host should take Status from E_Status of the preceding
> + * PIO Setup FIS.
> + */
> + if (qc->tf.protocol == ATA_PROT_PIO && qc->dma_dir == DMA_FROM_DEVICE &&
> + !(qc->flags & ATA_QCFLAG_FAILED))
> + qc->result_tf.command = (rx_fis + RX_FIS_PIO_SETUP)[15];
Shouldn't we be reading the entire TF from the PIO setup FIS and then
just replacing the command register value with the E_Status field? It
looks like that's the only field in the TF that's being set here.
> + else
> + ata_tf_from_fis(rx_fis + RX_FIS_D2H_REG, &qc->result_tf);
>
> - ata_tf_from_fis(d2h_fis, &qc->result_tf);
> return true;
> }
>
>
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