From: Tejun <htejun@gmail.com>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: linux-ide@vger.kernel.org, albertcc@tw.ibm.com
Subject: Re: [PATCH 06/12] sata_sil: convert to new reset mechanism
Date: Sun, 29 Jan 2006 08:17:04 +0900 [thread overview]
Message-ID: <43DBFB70.4050002@gmail.com> (raw)
In-Reply-To: <43DBB34B.1050302@pobox.com>
Jeff Garzik wrote:
> Tejun Heo wrote:
>
>> Convert sata_sil to use new reset mechanism. sata_sil is fairly
>> generic and can directly use std routine.
>>
>> Signed-off-by: Tejun Heo <htejun@gmail.com>
>
>
> Major NAK.
>
> The placement of every hardware register read/write has been very
> carefully laid out, and your reset hardware re-orders a lot of that.
> Code re-ordering is fine. Changing the order of I/O operations is not.
> With this patch, sata_sil fails to wake up and initialize the SATA phy!
>
> Proper code transformation is art. You're doing really well, but this
> was a bit of a hiccup. You should have presented a series of patches
> which changed over to your new ata_drive_probe_reset() stuff, while -not
> changing the hardware operations at all-. Like a mathematical solution,
> your code is then provably correct. If there is a regression, then you
> know it is a driver bug, and not a problem with hardware acting weird.
>
> If the driver can access the SATA PHY registers, the very first thing it
> should usually do is the code in sata_std_hardreset()... everything
> except the 0x301 value write. Or in other words, follow the code in
> __sata_phy_reset() PRECISELY (presuming that ATA_FLAG_SATA_RESET is not
> set).
>
> sata_sil hardware initialization order and behavior should not change at
> all [though certainly you will change it sometime in the future].
Okay, I see. I'll rewrite those parts such that it acts in the same way
as the original reset.
> So... I will drop all other patches from you, let you resync with the
> latest stuff in libata-dev.git#upstream (NOTE: renamed from
> upstream-2.6.17 to upstream), and wait for your next barrage of patches ;-)
It's lunar new year here and I am away from office until 1st Feb, so it
will take me some time.
Thanks a lot for all your help and guidance. It's been a great year.
Happy (lunar) new year, guys. :-)
--
tejun
next prev parent reply other threads:[~2006-01-28 23:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-24 8:05 [PATCHSET] libata: new reset mechanism, take#2 Tejun Heo
2006-01-24 8:05 ` [PATCH 01/12] libata: export ata_busy_sleep Tejun Heo
2006-01-27 4:18 ` Jeff Garzik
2006-01-24 8:05 ` [PATCH 10/12] ata_piix: convert sata to new reset mechanism Tejun Heo
2006-01-24 8:05 ` [PATCH 05/12] libata: implement standard reset component operations and ->probe_reset Tejun Heo
2006-01-28 1:58 ` Jeff Garzik
2006-01-24 8:05 ` [PATCH 02/12] libata: modify ata_dev_try_classify Tejun Heo
2006-01-27 4:20 ` Jeff Garzik
2006-01-24 8:05 ` [PATCH 09/12] ata_piix: convert pata to new reset mechanism Tejun Heo
2006-01-24 8:05 ` [PATCH 03/12] libata: new ->probe_reset operation Tejun Heo
2006-01-24 8:05 ` [PATCH 12/12] ahci: add softreset Tejun Heo
2006-01-24 8:05 ` [PATCH 08/12] sata_sil24: add hardreset Tejun Heo
2006-01-24 8:05 ` [PATCH 06/12] sata_sil: convert to new reset mechanism Tejun Heo
2006-01-28 18:09 ` Jeff Garzik
2006-01-28 18:27 ` Jeff Garzik
2006-01-28 23:17 ` Tejun [this message]
2006-01-29 2:41 ` Jeff Garzik
2006-01-24 8:05 ` [PATCH 07/12] sata_sil24: " Tejun Heo
2006-01-24 8:05 ` [PATCH 04/12] libata: implement ata_drive_probe_reset() Tejun Heo
2006-01-28 1:58 ` Jeff Garzik
2006-01-24 8:05 ` [PATCH 11/12] ahci: convert to new reset mechanism Tejun Heo
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