Re: [git patch] atang tree: enhanced SSD detection

From: Bartlomiej Zolnierkiewicz
Date: Tue Feb 23 2010 - 07:21:27 EST


On Tuesday 23 February 2010 07:08:21 am Jeff Garzik wrote:
> On 02/21/2010 12:41 PM, Bartlomiej Zolnierkiewicz wrote:
> > DISCLAIMER: the fact of getting patches merged into atang tree means
> > that from now on they will be getting updates for changes happening
> > in atang tree and it should not be treated as an indication regarding
> > decisions taken by 'upstream' kernel trees
> >
> >
> > Improve SSD detection so block layer optimizations can be applied
> > to many more SSD devices.
> >
> >
> > The following changes since commit 17c619273d412ed7b6120e448f87b2329457fc90:
> > Bartlomiej Zolnierkiewicz (1):
> > pata_oldpiix: enable parallel scan
> >
> > are available in the git repository at:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/bart/misc.git atang-v4.7
> >
> > Bartlomiej Zolnierkiewicz (1):
> > libata: enhanced SSD detection
> >
> > drivers/ata/libata-core.c | 3 +++
> > drivers/ata/libata-scsi.c | 18 ++++++++++--------
> > include/linux/libata.h | 1 +
> > 3 files changed, 14 insertions(+), 8 deletions(-)
> >
> >
> > commit ded92e0d01fbb7f27bec7a35606847a2547e95e0
> > Author: Bartlomiej Zolnierkiewicz<bzolnier@xxxxxxxxx>
> > Date: Sun Feb 21 18:31:18 2010 +0100
> >
> > libata: enhanced SSD detection
> >
> > Many SSD devices predate or just don't implement non-rotational
> > media type advertisement through the word 217 of the id block so
> > check also the product id for 'SSD' substring to automatically
> > detect SSD devices and apply relevant block layer optimizations.
> >
> > This is based on earlier Jeff Garzik's patch from April 2009:
> > http://lkml.org/lkml/2009/4/7/495
> >
> > While at it:
> > - cleanup ata_scsi_dev_config() a bit
> >
> > Tested with ASUS-PHISON SSD devices found in Asus Eee 901.
> >
> > Cc: Jeff Garzik<jeff@xxxxxxxxxx>
> > Signed-off-by: Bartlomiej Zolnierkiewicz<bzolnier@xxxxxxxxx>
>
> Yes, I agree we need something like this. I will review for atang
> dependencies, and then make sure it gets applied to upstream.
>
> The previous discussion of this approach concluded weakly with "poor
> heuristic", but a better approach did not materialize.
>
> One question, though: why did you drop ata_id_is_ssd() test?

This test is not in the 'upstream' any longer as 'standard' detection
is now handled through libata-scsi emulation layer (after SSD related
SCSI changes made by Martin K. Petersen, commit f17259a etc).

--
Bartlomiej Zolnierkiewicz
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