Re: [RFC 1/2] block: implement an unprep function corresponding directly to prep

Mark Lord
2010-08-03T03:01:25Z

On 10-07-05 05:54 PM, Mark Lord wrote:
>> On 05/07/10 03:24 PM, Christoph Hellwig wrote:
>>>
>>> What codebase were you testing on? Sorry, but curently I'm a bit lost
>>> in the maze of patches. I've got both and intel and an OCZ SSD
> ..
>
> Do you, or anyone else with one, know what the upper limit is on
> TRIM operations with the Intel SSDs ?
>
> I need to know the maximum amount of TRIM ranges they will process
> in a single command.
>
> Eg. Indilinx-based SSDs don't appear to have a limit -- they'll accept
> a TRIM command with thousands of LBA ranges included.
>
> Sandforce-based SSDs appear to restrict things to max 4KB of range data.
>
> So.. what about Intel?

Well, I still don't know about Intel drives -- anyone?

But for the latest hardware, some manufacturers are now reporting
their TRIM limits in word[105] of the identify data,
as described (optional) in the latest draft ATA ACS-2 specs.

It appears that Sandforce drives officially only allow 512-bytes of range data.
So I'll limit hdparm's TRIM functions to match word[105] when it is specified.

The Indilinx drives I have here don't report anything in word[105], though.

Cheers