From: Tejun Heo <htejun@gmail.com>
To: Jeff Garzik <jeff@garzik.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Mark Lord <liml@rtr.ca>,
linux-ide@vger.kernel.org
Subject: Re: Polling (was Re: [PATCHSET 2/2] implement PMP support, take 6)
Date: Fri, 28 Sep 2007 22:24:55 -0700 [thread overview]
Message-ID: <46FDE1A7.6030102@gmail.com> (raw)
In-Reply-To: <46FDADD9.9050007@garzik.org>
Jeff Garzik wrote:
> Polling ALREADY makes the job of fixing SAS/SATA exception handling
> difficult. Expanding polling to something SAS/SATA controllers treat as
> fundamentally irq-driven and integrated with the rest of the command
> flow is moving in the wrong direction.
>
> To re-re-re-summarize, polling in PMP is fundamentally broken for an
> ENTIRE CLASS OF HARDWARE that we actively support today. And
> jgarzik/misc-2.6.git#sas is adding two more controllers to that list.
As an interim solution, it doesn't make anything worse tho. Those
drivers don't support PMP anyway. After rc1 merge, polling PMP access
can be replaced with new qc_issue (probably ata_exec_internal) based code.
The question here is whether it's worth to include PMP support with
polling PMP register access as an interim solution for 2.6.24. I think
it will be beneficial for both user convenience and testing as long as
the said change is made soon after -rc1.
My vote is yes but this kind of decision ultimately falls on the
subsystem maintainer, so it's your call, Jeff.
Thanks.
--
tejun
next prev parent reply other threads:[~2007-09-29 5:26 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-23 4:19 [PATCHSET 2/2] implement PMP support, take 6 Tejun Heo
2007-09-23 4:19 ` [PATCH 01/10] libata-pmp: update ata_eh_reset() for PMP Tejun Heo
2007-09-23 4:19 ` [PATCH 02/10] libata-pmp: implement Port Multiplier support Tejun Heo
2007-09-23 4:19 ` [PATCH 07/10] sata_sil24: implement PORT_RST Tejun Heo
2007-09-23 4:19 ` [PATCH 06/10] sata_sil24: implement PMP support Tejun Heo
2007-09-23 4:19 ` [PATCH 04/10] libata-pmp: extend ACPI support to cover PMP Tejun Heo
2007-09-23 4:19 ` [PATCH 03/10] libata-pmp: hook PMP support and enable it Tejun Heo
2007-09-23 4:19 ` [PATCH 08/10] ahci: implement PMP support Tejun Heo
2007-09-23 4:19 ` [PATCH 05/10] libata-pmp: implement qc_defer for command switching " Tejun Heo
2007-09-23 4:19 ` [PATCH 09/10] ahci: move host flags over to pi.private_data Tejun Heo
2007-09-23 4:19 ` [PATCH 10/10] ahci: implement AHCI_HFLAG_NO_PMP Tejun Heo
2007-09-26 2:09 ` Polling (was Re: [PATCHSET 2/2] implement PMP support, take 6) Jeff Garzik
2007-09-26 2:12 ` Jeff Garzik
2007-09-26 8:41 ` Tejun Heo
2007-09-28 12:10 ` Tejun Heo
2007-09-28 13:54 ` Jeff Garzik
2007-09-28 14:18 ` Tejun Heo
2007-09-28 14:57 ` Alan Cox
2007-09-28 15:20 ` Jeff Garzik
2007-09-28 15:43 ` Alan Cox
2007-09-28 15:40 ` Jeff Garzik
2007-09-28 20:00 ` Mark Lord
2007-09-29 1:49 ` Jeff Garzik
2007-09-29 3:29 ` Jeff Garzik
2007-09-29 4:58 ` Andrew Morton
2007-09-29 5:09 ` Jeff Garzik
2007-09-29 16:51 ` Greg Freemyer
2007-09-29 20:56 ` Alan Cox
2007-10-01 12:28 ` Jeff Garzik
2007-09-28 15:22 ` Jeff Garzik
2007-09-28 16:48 ` Tejun Heo
2007-09-28 20:02 ` Mark Lord
2007-09-28 20:25 ` Bartlomiej Zolnierkiewicz
2007-09-28 21:03 ` Alan Cox
2007-09-29 1:43 ` Jeff Garzik
2007-09-29 5:24 ` Tejun Heo [this message]
2007-10-01 13:31 ` Jeff Garzik
2007-10-02 0:11 ` Tejun Heo
2007-10-02 14:25 ` Alan Cox
2007-10-02 14:30 ` Jeff Garzik
2007-09-29 12:32 ` Mark Lord
2007-10-01 12:38 ` Jeff Garzik
2007-10-02 0:12 ` Tejun Heo
2007-10-02 12:56 ` Jeff Garzik
2007-10-02 13:06 ` Mark Lord
2007-10-02 13:30 ` Jeff Garzik
2007-10-06 22:02 ` Tejun Heo
2007-10-09 2:09 ` Jeff Garzik
2007-10-09 6:54 ` Tejun Heo
2007-09-28 14:20 ` Mark Lord
2007-09-28 15:36 ` Jeff Garzik
2007-09-28 15:55 ` Alan Cox
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