NV Cache Feature Support in libata

NV Cache Feature Support in libata

[Fajun Chen]

Hi All,

I'm not aware of any NV cache (vista feature documented in
ata-atapi-8) support in libata. Is this supported or any plan to
support it in the future?

Thanks,
Fajun

Re: NV Cache Feature Support in libata

[Timothy Bisson]

On Feb 9, 2007, at 10:25 AM, Fajun Chen wrote:

> I'm not aware of any NV cache (vista feature documented in
> ata-atapi-8) support in libata. Is this supported or any plan to
> support it in the future?

It is already supported through the HDIO_DRIVE_CMD ioctl - pass 0xb6  
as the command register value.

I think the interesting question is, how can we leverage the NV Cache  
in the block and file system layers to improve power and performance.  
One probably obvious option is to enter NV Cache Power Mode when  
laptop mode is enabled.

Tim

Re: NV Cache Feature Support in libata

[Fajun Chen]

Did you refer to "HDIO_DRIVE_CMD ioctl" in old IDE code? I couldn't
get it working on libata.  Based on libata-scsi code, only PIO data in
and Non-data protocol are supported for HDIO_DRIVE_CMD while NV Cache
commands requires DMA based on ATA8 spec.

I tried to use ATA pass through command for NV Cache commands. For
instance,  I implemented Add LBA to Pinned Set command just like Write
DMA Extended with the differences in command, feature and LBA register
bit 0, but I got "protocol mismatch" error from device.

I would appreciate any information in regard to libata support on NV
Cache commands.

Thanks,
Fajun


On 2/9/07, Timothy Bisson <timbisson@sbcglobal.net> wrote:
>
>
> On Feb 9, 2007, at 10:25 AM, Fajun Chen wrote:
>
>
> I'm not aware of any NV cache (vista feature documented in
>
> ata-atapi-8) support in libata. Is this supported or any plan to
>
> support it in the future?
> It is already supported through the HDIO_DRIVE_CMD ioctl - pass 0xb6 as the
> command register value.
>
> I think the interesting question is, how can we leverage the NV Cache in the
> block and file system layers to improve power and performance. One probably
> obvious option is to enter NV Cache Power Mode when laptop mode is enabled.
>
> Tim