From: Valdis.Kletnieks@vt.edu
To: scameron@beardog.cce.hp.com
Cc: Tomas Henzl <thenzl@redhat.com>,
james.bottomley@hansenpartnership.com,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
smcameron@yahoo.com, akpm@linux-foundation.org,
mikem@beardog.cce.hp.com
Subject: Re: [PATCH 01/16] hpsa: do readl after writel in main i/o path to ensure commands don't get lost.
Date: Wed, 04 May 2011 13:28:21 -0400 [thread overview]
Message-ID: <10639.1304530101@localhost> (raw)
In-Reply-To: Your message of "Wed, 04 May 2011 07:52:12 CDT." <20110504125212.GC5997@beardog.cce.hp.com>
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On Wed, 04 May 2011 07:52:12 CDT, scameron@beardog.cce.hp.com said:
> On Wed, May 04, 2011 at 01:15:50PM +0200, Tomas Henzl wrote:
> > On 05/03/2011 09:58 PM, Stephen M. Cameron wrote:
> > > From: Stephen M. Cameron <scameron@beardog.cce.hp.com>
> > > dev_dbg(&h->pdev->dev, "Sending %x, tag = %x\n", c->busaddr,
> > > c->Header.Tag.lower);
> > > writel(c->busaddr, h->vaddr + SA5_REQUEST_PORT_OFFSET);
> > > + (void) readl(h->vaddr + SA5_REQUEST_PORT_OFFSET);
> I just put it there to make it clear that it ignoring the return of readl is
> done intentionally, not accidentally. If this goes against some coding convention,
> whatever, I'm not super attached to the (void), but I did put it there on purpose,
> and would have done it in cciss as well, had I thought of it at the time.
This probably needs a comment like
/* don't care - dummy read just to force write posting to chipset */
or similar. I'm assuming it's just functioning as a barrier-type flush of some sort?
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next prev parent reply other threads:[~2011-05-04 17:28 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-03 19:58 [PATCH 00/16] hpsa: May 3, 2011 updates Stephen M. Cameron
2011-05-03 19:58 ` [PATCH 01/16] hpsa: do readl after writel in main i/o path to ensure commands don't get lost Stephen M. Cameron
2011-05-04 11:15 ` Tomas Henzl
2011-05-04 12:52 ` scameron
2011-05-04 13:34 ` Tomas Henzl
2011-05-04 17:28 ` Valdis.Kletnieks [this message]
2011-05-04 17:37 ` Matthew Wilcox
2011-05-04 17:54 ` Valdis.Kletnieks
2011-05-05 18:35 ` Mike Miller
2011-05-23 11:37 ` Tomas Henzl
2011-05-25 15:20 ` Miller, Mike (OS Dev)
2011-05-26 12:13 ` Tomas Henzl
2011-05-26 14:53 ` Miller, Mike (OS Dev)
2011-05-03 19:58 ` [PATCH 02/16] hpsa: add readl after writel in interrupt mask setting code Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 03/16] hpsa: remove unused parameter from hpsa_complete_scsi_command() Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 04/16] hpsa: delete old unused padding garbage Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 05/16] hpsa: do a better job of detecting controller reset failure Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 06/16] hpsa: wait longer for no-op to complete after resetting controller Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 07/16] hpsa: factor out cmd pool allocation functions Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 08/16] hpsa: factor out irq request code Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 09/16] hpsa: increase time to wait for board reset Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 10/16] hpsa: clarify messages around reset behavior Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 11/16] hpsa: remove atrophied hpsa_scsi_setup function Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 12/16] hpsa: use new doorbell-bit-5 reset method Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 13/16] hpsa: do soft reset if hard reset is broken Stephen M. Cameron
2011-05-03 19:59 ` [PATCH 14/16] hpsa: remove superfluous sleeps around reset code Stephen M. Cameron
2011-05-03 20:00 ` [PATCH 15/16] hpsa: do not attempt PCI power management reset method if we know it won't work Stephen M. Cameron
2011-05-03 20:00 ` [PATCH 16/16] hpsa: add P2000 to list of shared SAS devices Stephen M. Cameron
2011-05-17 10:12 ` James Bottomley
2011-05-17 13:26 ` scameron
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