Message-ID: <45D6436C.4060209@garzik.org>
Date: Fri, 16 Feb 2007 18:51:08 -0500
From: Jeff Garzik <jeff@garzik.org>
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To: Robert Hancock <hancockr@shaw.ca>
CC: Tobias Diedrich <ranma+kernel@tdiedrich.de>,
       Linux Kernel ML <linux-kernel@vger.kernel.org>,
       linux-ide@vger.kernel.org, Alan <alan@lxorguk.ukuu.org.uk>
Subject: Re: pata_amd dropping to PIO on resume
References: <fa.q7ZuddHInqn2dVlS+EWjXjPvFC8@ifi.uio.no> <45D63BCE.2080700@shaw.ca>
In-Reply-To: <45D63BCE.2080700@shaw.ca>
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Robert Hancock wrote:
> Tobias Diedrich wrote:
>> Possibly a known issue:
>>
>> After resume pata_amd drops from UDMA/33 to PIO on my system.
>> Reloading the module puts both attached optical drives (master and
>> slave) back to UDMA/33.
>>
>> AFAICS "simplex DMA is claimed by other device, disabling DMA" seems
>> to be causing it to drop to PIO (but only after a suspend/resume
>> cycle, not on boot or module load).
>>
>> Burning a DVD with 6x speed using PIO makes heavy use of burnproof
>> and makes the whole system quite sluggish. :)
> 
> Yes, the fact that it's going into simplex mode is the problem, it 
> wasn't in simplex to start with. It looks like pata_amd does an 
> ata_pci_clear_simplex only for certain chip models, maybe this model 
> needs it as well?
> 

Deleting the ata_pci_clear_simplex() call, then adding 
ATA_FLAG_IGN_SIMPLEX to the ata_port_info info[] array, is also worth 
trying.

	Jeff


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