Will update you on how it goes .
Generally the only reason for me to do it , is to check how does the
SATA drive acts when it receives two identical tags.
(Erroneous scenario).
Is there a simple way to assure that the user space application is the
only one which writes to this disk ?
The disk is a seperate drive , not the System one , and generally the
user space is the only one touching it.
Nothing is installed on it.
Which other process in the system might touch it ?
Will use your help.
Thanks
On Fri, May 22, 2009 at 2:53 AM, Gwendal Grignou <gwendal@xxxxxxxxxx> wrote:
> 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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