From: Jeff Garzik <jgarzik@pobox.com>
To: albertl@mail.com
Cc: Tejun Heo <htejun@gmail.com>, linux-ide@vger.kernel.org
Subject: Re: [PATCHSET] implement and use port_task
Date: Tue, 07 Mar 2006 02:21:09 -0500 [thread overview]
Message-ID: <440D3465.1040203@pobox.com> (raw)
In-Reply-To: <440D2497.7050504@tw.ibm.com>
Albert Lee wrote:
> Something related to the PIO HSM.
> After the task renaming by this patchset, the task name is changed from pio_task to port_task.
> Should we add polling DMA support to the polling HSM?
> It could make the polling HSM more complete.
>
> Polling DMA does no performance gain. However, DMA has crc check,
> so it won't be worse than PIO when irq is not working.
Polling DMA support with nIEN=1 is theoretically invalid. You are not
supposed to touch the ATA shadow register set until after receiving an
irq event.
On chipsets where nIEN=0 and the chip's IntrMask is also zero, its doable.
I'm satisfied with simply never doing polling DMA, and change our mind
only if a critical need arises.
Jeff
next prev parent reply other threads:[~2006-03-07 7:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-05 6:28 [PATCHSET] implement and use port_task Tejun Heo
2006-03-07 6:13 ` Albert Lee
2006-03-07 7:01 ` Tejun Heo
2006-03-07 7:21 ` Jeff Garzik [this message]
2006-03-09 8:39 ` Albert Lee
-- strict thread matches above, loose matches on Subject: below --
2006-03-05 6:29 Tejun Heo
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