Date: Wed, 25 Apr 2007 00:13:30 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: "Daniel O'Connor" <doconnor@gsoft.com.au> Cc: freebsd-current@freebsd.org Subject: Re: ATA FLUSHCACHE Message-ID: <20070425071329.GC73385@funkthat.com> In-Reply-To: <200704242205.06243.doconnor@gsoft.com.au> References: <20070424051420.GA84831@mero.morphisms.net> <200704241942.40874.doconnor@gsoft.com.au> <462DEB4A.6050700@freebsd.org> <200704242205.06243.doconnor@gsoft.com.au>
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Daniel O'Connor wrote this message on Tue, Apr 24, 2007 at 22:04 +0930:
> On Tuesday 24 April 2007 21:04, Eric Anderson wrote:
> > > If it is a transient error then panicing seems to be about the
> > > worse response :)
> >
> > Doesn't a failed ATA FLUSHCACHE mean that the device could not
> > complete it's writing of cached bits to stable storage within the
> > timeout period? That seems to me that the flushcache should be called
> > more frequently then, so less writes have to be written out.
>
> I don't know what the exact semantics of the flush command are. Also I
> have no data on typical delays for flushes, etc..
>From the ATA spec:
If there is data in the write cache, that data shall be written to the
media. The BSY bit shall remain set to one until all data has been
successfully written or an error occurs.
NOTE -- This command may take longer than 30 s to complete.
So, if I read the timeout correctly as 1 second, that's woefully short..
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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