On Wed, May 20, 2009 at 2:20 PM, Dan Porat <dan.porat@xxxxxxxxx> wrote:
> Thank plenty for your answer.
>
> So , what is the best way to send NCQ through user space ?
> Is it possible to disable the tagging mechanism by the driver and only
> rely on the tag given by the user space ?
That's one solution, but that's quite risky, it can be difficult to
guarantee nobody else access the disk. Another one is to alter
ata_scsi_pass_thru() to use qc->tag in case of FPDMA command. It is
already calculated before we enter the translation function.
Let me know how it goes,
Gwendal.
>
> Thanks
>
>
> On Wed, May 20, 2009 at 10:53 PM, Gwendal Grignou <gwendal@xxxxxxxxxx> wrote:
>> Hi Dan,
>>
>> tf->nsect can not be calculated from user space: the tag must be
>> calculated by the driver.
>>
>> Gwendal.
>>
>> On Tue, May 19, 2009 at 11:11 AM, Dan Porat <dan.porat@xxxxxxxxx> wrote:
>>> As I have seen sg_io does not support NCQ in ATA passthrough.
>>> will changing the mapping function libata-scsi.c (line 2745) , work?
>>>
>>> If not , how else can I check the protocol (FPDMA) ?
>>> static u8
>>> 2725ata_scsi_map_proto(u8 byte1)
>>> 2726{
>>> 2727 switch((byte1 & 0x1e) >> 1) {
>>> 2728 case 3: /* Non-data */
>>> 2729 return ATA_PROT_NODATA;
>>> 2730
>>> 2731 case 6: /* DMA */
>>> 2732 case 10: /* UDMA Data-in */
>>> 2733 case 11: /* UDMA Data-Out */
>>> 2734 return ATA_PROT_DMA;
>>> 2735
>>> 2736 case 4: /* PIO Data-in */
>>> 2737 case 5: /* PIO Data-out */
>>> 2738 return ATA_PROT_PIO;
>>> 2739
>>> 2745 case 12: /* FPDMA */
>>> return ATA_PROT_NCQ
>>> 2740 case 0: /* Hard Reset */
>>> 2741 case 1: /* SRST */
>>> 2742 case 8: /* Device Diagnostic */
>>> 2743 case 9: /* Device Reset */
>>> 2744 case 7: /* DMA Queued */
>>>
>>> 2746 case 15: /* Return Response Info */
>>> 2747 default: /* Reserved */
>>> 2748 break;
>>> 2749 }
>>> 2750
>>> 2751 return ATA_PROT_UNKNOWN;
>>> 2752}
>>>
>>>
>>>
>>> Thanks
>>>
>>> Dan Porat
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>>
>
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