stupid SATA questions

stupid SATA questions

[Kumar Gala]

These questions were posed to me and I was hoping someone would have 
better knowledge about the works and usage of SATA then I do.  All of 
these questions are around understanding how important the performance 
of PIO mode is.

How often would one run in PIO mode?  Why would one run in PIO mode?

Thanks

- kumar

Re: stupid SATA questions

[Jeff Garzik]

Kumar Gala wrote:
> These questions were posed to me and I was hoping someone would have 
> better knowledge about the works and usage of SATA then I do.  All of 
> these questions are around understanding how important the performance 
> of PIO mode is.
> 
> How often would one run in PIO mode?  Why would one run in PIO mode?

Never.  No idea.  :)

Unless you have a broken device, or a command that cannot work with DMA 
(such as IDENTIFY DEVICE), PIO mode is quite pointless.  It is emulated 
under SATA, turned into FIS's on the SATA bus.

	Jeff

Re: stupid SATA questions

[Robert White]

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Since the title of the thread applies...

What command (or whatever) does one use to do things like set the power
controls on a libata-controlled SATA drive?  hdparm doesn't seem to do
anything but complain when I try to use the various features.

hdparm /dev/sda
/dev/sda:
 IO_support   =  0 (default 16-bit)
 ...

Does the "16-bit" mean anything or is it just a bogon?

Rob White

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Re: stupid SATA questions

[Jeff Garzik]

Robert White wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> 
> 
> Since the title of the thread applies...
> 
> What command (or whatever) does one use to do things like set the power
> controls on a libata-controlled SATA drive?  hdparm doesn't seem to do
> anything but complain when I try to use the various features.

You need "ATA passthru" (SMART support) in order for hdparm to work.


> hdparm /dev/sda
> /dev/sda:
>  IO_support   =  0 (default 16-bit)
>  ...
> 
> Does the "16-bit" mean anything or is it just a bogon?

This is hardcoded.  I doubt you will ever be able to change this.

	Jeff

RE: stupid SATA questions

[Robert White]

Howdy,

I cannot find the ATA passthru or SMART option in the 2.6.11.10 kernel anywhere near
the SCSI or ATA .  Is it somewhere obscure, has it been renamed, or am I looking in
totally the wrong place? (e.g. is this an option when building hdparm or something?)

Rob.

-----Original Message-----
From: Jeff Garzik [mailto:jgarzik@pobox.com] 
Sent: Wednesday, June 08, 2005 10:44 AM

You need "ATA passthru" (SMART support) in order for hdparm to work.

Re: stupid SATA questions

[jgarzik]

On Fri, Jun 10, 2005 at 11:51:26AM -0700, Robert White wrote:
> I cannot find the ATA passthru or SMART option in the 2.6.11.10 kernel anywhere near
> the SCSI or ATA .  Is it somewhere obscure, has it been renamed, or am I looking in
> totally the wrong place? (e.g. is this an option when building hdparm or something?)

It requires an additional patch; it has not been mergedsinceit still
has a few problems.

	Jeff

Re: stupid SATA questions

[Abhijit Bhopatkar]

On 6/11/05, jgarzik@pentafluge.infradead.org
<jgarzik@pentafluge.infradead.org> wrote:
> On Fri, Jun 10, 2005 at 11:51:26AM -0700, Robert White wrote:
> > I cannot find the ATA passthru or SMART option in the 2.6.11.10 kernel anywhere near
> > the SCSI or ATA .  Is it somewhere obscure, has it been renamed, or am I looking in
> > totally the wrong place? (e.g. is this an option when building hdparm or something?)
> 
> It requires an additional patch; it has not been mergedsinceit still
> has a few problems.

Can somebody please point me to the latest patches?
ATA pass thru should be a good thing to play with
I am waiting for SATA ATAPI support so that finally i can start
playing DVDs again under linux.

I have ICH6M chipset with DVD/CD-RW drive on my laptop. So if you need
some testing on that i am willing to do that.

Currently i am running on 2.6.11 with JG's 
"2.6.11-libata-dev1.patch.bz2 " patch and ATAPI tunred on in libata.h,
but apparently it still is not in working condition, are there
experimental patches which have atleast half working ATAPI in libata?

Or should i just wait for some more time ?.....
Thanks and reagards,

BAIN

RE: stupid SATA questions

[Aleksey Gorelov]

 
>From: linux-kernel-owner@vger.kernel.org 
>[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jeff Garzik
>Sent: Tuesday, June 07, 2005 11:01 AM
>To: Kumar Gala
>Cc: Linux Kernel list
>Subject: Re: stupid SATA questions
>
>Kumar Gala wrote:
>> These questions were posed to me and I was hoping someone would have 
>> better knowledge about the works and usage of SATA then I 
>do.  All of 
>> these questions are around understanding how important the 
>performance 
>> of PIO mode is.
>> 
>> How often would one run in PIO mode?  Why would one run in PIO mode?
>
>Never.  No idea.  :)

Some BIOSes/option ROMs do. Especially SATA RAID ones.
But unless you are using BIOS interrupts... 

Aleks

>
>Unless you have a broken device, or a command that cannot work 
>with DMA 
>(such as IDENTIFY DEVICE), PIO mode is quite pointless.  It is 
>emulated 
>under SATA, turned into FIS's on the SATA bus.
>
>	Jeff
>
>
>
>-
>To unsubscribe from this list: send the line "unsubscribe 
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>

Re: stupid SATA questions

[Jeff Garzik]

Aleksey Gorelov wrote:
>  
> 
>>From: linux-kernel-owner@vger.kernel.org 
>>[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jeff Garzik
>>Sent: Tuesday, June 07, 2005 11:01 AM
>>To: Kumar Gala
>>Cc: Linux Kernel list
>>Subject: Re: stupid SATA questions
>>
>>Kumar Gala wrote:
>>
>>>These questions were posed to me and I was hoping someone would have 
>>>better knowledge about the works and usage of SATA then I 
>>
>>do.  All of 
>>
>>>these questions are around understanding how important the 
>>
>>performance 
>>
>>>of PIO mode is.
>>>
>>>How often would one run in PIO mode?  Why would one run in PIO mode?
>>
>>Never.  No idea.  :)
> 
> 
> Some BIOSes/option ROMs do. Especially SATA RAID ones.
> But unless you are using BIOS interrupts... 

It doesn't matter what BIOS does, Linux SATA drivers don't use the BIOS.

	Jeff

RE: stupid SATA questions

[Aleksey Gorelov]

 
>From: Jeff Garzik [mailto:jgarzik@pobox.com] 
>Aleksey Gorelov wrote:
>>  
>> 
>>>From: linux-kernel-owner@vger.kernel.org 
>>>[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jeff Garzik
>>>Sent: Tuesday, June 07, 2005 11:01 AM
>>>To: Kumar Gala
>>>Cc: Linux Kernel list
>>>Subject: Re: stupid SATA questions
>>>
>>>Kumar Gala wrote:
>>>
>>>>These questions were posed to me and I was hoping someone 
>would have 
>>>>better knowledge about the works and usage of SATA then I 
>>>
>>>do.  All of 
>>>
>>>>these questions are around understanding how important the 
>>>
>>>performance 
>>>
>>>>of PIO mode is.
>>>>
>>>>How often would one run in PIO mode?  Why would one run in PIO mode?
>>>
>>>Never.  No idea.  :)
>> 
>> 
>> Some BIOSes/option ROMs do. Especially SATA RAID ones.
>> But unless you are using BIOS interrupts... 
>
>It doesn't matter what BIOS does, Linux SATA drivers don't use 
>the BIOS.

I probably missed something, but I did not see LINUX SATA DRIVERS in the
original question, I just saw SATA. Well, never mind then ;)

Aleks.