From: Jens Axboe <axboe@suse.de>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
"C.Y.M." <syphir@syphir.sytes.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Changes to ide-probe.c in 2.6.9-rc2 causing improper detection
Date: Tue, 14 Sep 2004 17:25:09 +0200 [thread overview]
Message-ID: <20040914152509.GA27892@suse.de> (raw)
In-Reply-To: <41470BBD.7060700@pobox.com>
On Tue, Sep 14 2004, Jeff Garzik wrote:
> Alan Cox wrote:
> >On Maw, 2004-09-14 at 07:06, Jens Axboe wrote:
> >
> >>Alan, I bet there are a lot of these. Maybe we should consider letting
> >>the user manually flag support for FLUSH_CACHE, at least it is in their
> >>hands then.
> >
> >
> >You are assuming the drive supports "FLUSH_CACHE" just because it
> >doesn't error it. Thats a good way to have accidents.
> >
> >The patch I posted originally did turn wcache off for barrier if no
> >flush cache support was present but had a small bug so that bit got
> >dropped.
>
>
> FWIW the libata test for checking whether it is OK to issue a flush is
>
> return ata_id_wcache_enabled(dev) ||
> ata_id_has_flush(dev) ||
> ata_id_has_flush_ext(dev);
>
> and if it passes that test,
>
> if ((tf->flags & ATA_TFLAG_LBA48) &&
> (ata_id_has_flush_ext(qc->dev)))
> tf->command = ATA_CMD_FLUSH_EXT;
> else
> tf->command = ATA_CMD_FLUSH;
>
> I wouldn't object to removing the "ata_id_wcache_enabled" test if people
> feel that it is unsafe.
Alan says it's unsafe for some of his flash cards, and I do believe they
say they have write caching enabled.
--
Jens Axboe
next prev parent reply other threads:[~2004-09-14 15:27 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-14 2:26 Changes to ide-probe.c in 2.6.9-rc2 causing improper detection C.Y.M.
2004-09-14 6:06 ` Jens Axboe
2004-09-14 7:03 ` C.Y.M.
2004-09-14 7:06 ` Jens Axboe
2004-09-14 7:15 ` Jens Axboe
2004-09-14 8:20 ` C.Y.M.
2004-09-14 8:28 ` Jens Axboe
2004-09-14 10:09 ` Alan Cox
2004-09-14 11:12 ` Jens Axboe
2004-09-14 10:35 ` Alan Cox
2004-09-14 11:43 ` Jens Axboe
2004-09-14 11:19 ` Alan Cox
2004-09-14 12:21 ` Jens Axboe
2004-09-14 11:37 ` Gene Heskett
2004-09-14 10:07 ` Alan Cox
2004-09-14 11:11 ` Jens Axboe
2004-09-14 11:59 ` Bartlomiej Zolnierkiewicz
2004-09-14 13:15 ` Jens Axboe
2004-09-14 10:05 ` Alan Cox
2004-09-14 11:09 ` Jens Axboe
2004-09-14 12:07 ` Bartlomiej Zolnierkiewicz
2004-09-14 15:18 ` Jeff Garzik
2004-09-14 15:25 ` Jens Axboe [this message]
2004-09-14 15:05 ` Alan Cox
2004-09-14 15:33 ` Mark Lord
2004-09-14 15:39 ` Mark Lord
2004-09-14 15:51 ` Jeff Garzik
2004-09-14 15:06 ` Alan Cox
2004-09-14 15:45 ` Jeff Garzik
2004-09-14 15:31 ` Mark Lord
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