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From: Jeff Garzik <jeff@garzik.org>
To: "Rogério Brito" <rbrito@ime.usp.br>
Cc: Michael Tokarev <mjt@tls.msk.ru>, Mark Lord <lkml@rtr.ca>,
	linux-kernel@vger.kernel.org
Subject: Re: Quick question about libata and hdparm
Date: Sun, 19 Apr 2009 17:27:52 -0400	[thread overview]
Message-ID: <49EB9758.3020506@garzik.org> (raw)
In-Reply-To: <20090419201132.GB2891@ime.usp.br>

Rogério Brito wrote:
> Hi, Jeff.
> 
> On Apr 19 2009, Jeff Garzik wrote:
>> Michael Tokarev wrote:
>>> Well, the kernel does a good job here in *almost* all cases.
>>> The problematic case is when a device has some bad/unreadable
>>> blocks/sectors.  When such a place occurs on read, libata
>>> (or whatever it is) performs several retries, each time
>>> using "less aggressive" settings - like reducing UDMA and
>>> PIO mode till the lowest possible PIO/33.  And the device
>>> stays in that mode until reboot, even if the problematic
>>> sector has been relocated.  So it'd be nice to be able to
>>> reset the mode back in such cases.
>> Do you have a log?
> 
> I have a log here of libata reducing UDMA speed. I don't know if this is
> any hardware problem or not (I think not), but I do see libata
> complaining and reducing the speed of the drive.

Well, it's supposed to reduce speed in several circumstances... just not 
Michael's.  :)

	Jeff




  reply	other threads:[~2009-04-19 21:28 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-19  0:22 Quick question about libata and hdparm Rogério Brito
2009-04-19  6:31 ` Robert Hancock
2009-04-19 12:33 ` Mark Lord
2009-04-19 12:44   ` Michael Tokarev
2009-04-19 12:57     ` Jeff Garzik
2009-04-19 13:06       ` Michael Tokarev
2009-04-19 20:11       ` Rogério Brito
2009-04-19 21:27         ` Jeff Garzik [this message]
2009-04-20 17:35           ` Rogério Brito
2009-04-20 18:40             ` Alan Cox
2009-04-20 20:41               ` Rogério Brito
2009-04-20 21:16                 ` Alan Cox
2009-04-20 20:31             ` Bartlomiej Zolnierkiewicz
2009-04-20 20:45               ` Rogério Brito
2009-04-20 21:19               ` Alan Cox
2009-04-20 22:57                 ` Rogério Brito
2009-04-21  5:32                 ` Rogério Brito
2009-04-21 12:59                   ` Bartlomiej Zolnierkiewicz
2009-04-23  5:56                     ` Rogério Brito
2009-04-23 21:31                       ` Bartlomiej Zolnierkiewicz
2009-04-24  3:00                         ` Rogério Brito
2009-05-01  9:18                           ` Rogério Brito
2009-05-01 10:31                             ` Alan Cox
2009-05-01 11:50                               ` Rogério Brito
2009-05-01 13:16                                 ` Alan Cox
2009-05-01 14:19                                 ` Rogério Brito
2009-05-01 11:20                             ` Bartlomiej Zolnierkiewicz
2009-05-11 18:34               ` Jeff Garzik
2009-04-19 20:03   ` Rogério Brito
2009-04-19 23:41     ` Mark Lord

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