On Thu, Oct 14, 2010 at 3:38 PM, Mark Lord <kernel@xxxxxxxxxxxx> wrote:
> On 10-10-14 04:53 AM, Tejun Heo 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))
>
> ..
>
> I'm not certain, but doesn't this problem also affect DMA_TO_DEVICE PIO
> commands?
> Eg. SECURITY_ERASE_PREPARE and PIO_WRITE ?
No, PIO data-out commands send a D2H register FIS after completion. It
appears that PIO data-in is the only special case.
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