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From: Robert Hancock <hancockr@shaw.ca>
To: linux-kernel@vger.kernel.org
Cc: "Larry Walton" <lwalton@real.com>,
	"Björn Steinbrink" <B.Steinbrink@gmx.de>,
	jeff@garzik.org, htejun@gmail.com, jens.axboe@oracle.com
Subject: Re: SATA exceptions with 2.6.20-rc5
Date: Thu, 18 Jan 2007 18:09:50 -0600	[thread overview]
Message-ID: <45B00C4E.4040803@shaw.ca> (raw)
In-Reply-To: <fa.O3RzvckSjB73Y0uL8P1nTXDRd6U@ifi.uio.no>

I heard from Larry Walton who was apparently seeing this problem as 
well. He tried my recent "sata_nv: cleanup ADMA error handling v2" patch 
and originally thought it fixed the problem, but it turned out to only 
make it happen less often.

I wouldn't expect that patch to have an effect on this problem. If it 
seems to reduce the frequency that would tend to be further evidence of 
  some kind of timing-related issue where the code change just happens 
to make a difference.

I'll see if I can come up with a debug patch for people having this 
problem to try, which prints out when a flush command is issued and what 
interrupts happen when a flush is pending.

There is one important difference between ADMA and non-ADMA mode for 
non-DMA commands like flushes, which didn't come to mind before: ADMA 
mode uses MMIO registers on the controller whereas non-ADMA mode uses 
legacy IO registers. Posted write flushing is a concern with MMIO 
registers but not with PIO, the libata core is supposed to handle this 
but maybe it doesn't in some case(s). In fact, just looking at 
libata-sff.c there's this comment on the ata_exec_command_mmio function:

  *      FIXME: missing write posting for 400nS delay enforcement

That seems a bit suspicious..

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/


       reply	other threads:[~2007-01-19  0:11 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.U/G88R1fWKOeQK3EBPHKK4MeRsQ@ifi.uio.no>
     [not found] ` <fa.2D0TIXbVTOgZmGg9ZJU+R7te70k@ifi.uio.no>
     [not found]   ` <fa.hMhdefkReYJ4idUyqqEWJFnWUBE@ifi.uio.no>
     [not found]     ` <fa.8TPWeOrcwkkHutPX5NOcJsTBO8Y@ifi.uio.no>
     [not found]       ` <fa.b92BqwV090pDj7q0iBG6BChksbI@ifi.uio.no>
     [not found]         ` <fa.O3RzvckSjB73Y0uL8P1nTXDRd6U@ifi.uio.no>
2007-01-19  0:09           ` Robert Hancock [this message]
2007-01-19  0:52             ` Björn Steinbrink
     [not found] <fa.1kBz5luWz8nR0lLqm1VD4hZZYdw@ifi.uio.no>
     [not found] ` <fa.QZxgjxcwtENaZNY24NMTlKBSgIM@ifi.uio.no>
     [not found]   ` <fa.fkPTbUGmKc/1pt0eD6TE4d02n+Q@ifi.uio.no>
     [not found]     ` <fa.6iQt5OtHZ3x5w8eYbLxwULhLTJ0@ifi.uio.no>
     [not found]       ` <fa.1aqo3IxNGJClHcBVZNTagX6bL9o@ifi.uio.no>
     [not found]         ` <fa.rI60BGlFbSyfLyumqmgiOfDqCI4@ifi.uio.no>
2007-01-23 23:18           ` Robert Hancock
2007-01-24  0:39             ` Björn Steinbrink
2007-02-03  1:42               ` Björn Steinbrink
2007-02-03  5:48                 ` Robert Hancock
2007-02-04  1:13                   ` Björn Steinbrink
2007-02-09 12:03                     ` Björn Steinbrink
2007-01-24  8:24             ` Ian Kumlien
2007-01-24 14:41               ` Björn Steinbrink
     [not found] <fa.ow4pXUncgdZmfLf3oyfrn1W+Bk0@ifi.uio.no>
     [not found] ` <fa.SoSeidhDuEr/K0kN+L4vW61Vpnc@ifi.uio.no>
     [not found]   ` <fa.m8QbVQMhuOshKzTdlSjNjOhaNcc@ifi.uio.no>
     [not found]     ` <fa.hDS02YCM8Tv1/STeTpJGEQD/49s@ifi.uio.no>
     [not found]       ` <fa.eqBbU9XvtTizNMpuUjctnk8vuOI@ifi.uio.no>
     [not found]         ` <fa.4QxeKMcmkoyhlL26AivZV6BFQJQ@ifi.uio.no>
2007-01-23  1:24           ` Robert Hancock
2007-01-23  1:34             ` Alistair John Strachan
2007-01-23  1:41               ` Robert Hancock
2007-01-23 15:29                 ` Larry Walton
2007-01-23  2:44             ` Björn Steinbrink
2007-01-23  5:03               ` Robert Hancock
2007-01-20 15:03 Ian Kumlien
2007-01-20 19:59 ` Robert Hancock
2007-01-20 21:43   ` Alistair John Strachan
2007-01-20 22:11     ` Ian Kumlien
     [not found] <fa.hif5u4ZXua+b0mVNaWEcItWv9i0@ifi.uio.no>
2007-01-14 23:43 ` Robert Hancock
2007-01-15  0:22   ` Jeff Garzik
2007-01-15  0:34     ` Björn Steinbrink
2007-01-15  2:47       ` Björn Steinbrink
2007-01-15  2:25     ` Robert Hancock
2007-01-15  2:53       ` Jens Axboe
2007-01-15 13:42         ` Jeff Garzik
2007-01-16  0:23           ` Jens Axboe
2007-01-16  0:36             ` Robert Hancock
2007-01-16  1:51               ` Jeff Garzik
2007-01-16  1:51             ` Jeff Garzik
2007-01-22 18:17               ` Eric D. Mudama
2007-01-15 21:17   ` Björn Steinbrink
2007-01-15 23:46     ` Björn Steinbrink
2007-01-16  0:34       ` Robert Hancock
2007-01-16  1:35         ` Björn Steinbrink
2007-01-16  3:00           ` Robert Hancock
2007-01-16  1:53         ` Jeff Garzik
2007-01-19 15:05           ` Alistair John Strachan
2007-01-19 19:51             ` chunkeey
2007-01-20  2:41             ` Robert Hancock
2007-01-20  2:47               ` Alistair John Strachan
2007-01-20  4:15               ` Björn Steinbrink
     [not found]               ` <20070120072755.GA4652@atjola.homenet>
2007-01-20  7:50                 ` Björn Steinbrink
2007-01-20 18:50               ` Chr
2007-01-20 22:32               ` Chr
2007-01-21  1:50                 ` Robert Hancock
2007-01-21  3:34                   ` Jeff Garzik
2007-01-21  4:54                     ` Björn Steinbrink
2007-01-21  6:39                       ` Robert Hancock
2007-01-21  8:36                         ` Björn Steinbrink
2007-01-21 17:34                           ` Chr
2007-01-21 18:01                             ` Björn Steinbrink
2007-01-21 20:13                               ` Chr
2007-01-22  2:39                                 ` Tejun Heo
2007-01-22 12:32                                   ` Chr
2007-01-21 18:40                           ` Björn Steinbrink
2007-01-21 19:58                             ` Robert Hancock
2007-01-21 22:08                               ` Björn Steinbrink
2007-01-21 22:11                                 ` Björn Steinbrink
2007-01-21 22:26                                   ` Robert Hancock
2007-01-21 22:27                               ` Björn Steinbrink
2007-01-22  0:17                                 ` Robert Hancock
2007-01-22 16:12                                   ` Björn Steinbrink
2007-01-22 16:57                                     ` Björn Steinbrink
2007-01-22 17:53                                       ` Björn Steinbrink
2007-01-19 14:53         ` Alistair John Strachan
  -- strict thread matches above, loose matches on Subject: below --
2007-01-14 22:44 Björn Steinbrink
2007-01-15  6:48 ` Mikael Pettersson
2007-01-15 13:43   ` Jeff Garzik
2007-01-15 13:47   ` Björn Steinbrink

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