From: Andi Kleen <andi@firstfloor.org>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Prakash, Sathya" <Sathya.Prakash@lsi.com>, linux-scsi@vger.kernel.org
Subject: Re: Query regarding modifying the DMA Mask based on the available memory in the system
Date: Thu, 17 Apr 2008 18:10:54 +0200 [thread overview]
Message-ID: <4807768E.20302@firstfloor.org> (raw)
In-Reply-To: <1208446607.3150.16.camel@localhost.localdomain>
James Bottomley wrote:
> On Thu, 2008-04-17 at 17:06 +0200, Andi Kleen wrote:
>> James Bottomley wrote:
>>> On Thu, 2008-04-17 at 16:44 +0200, Andi Kleen wrote:
>>>>> For drivers that can alter their descriptor types, we have this
>>>>> function:
>>>>>
>>>>> dma_get_required_mask()
>>>> Are you sure we have it? It seems to be in drivers/base/platform.c
>>>> conditional on ARCH_HAS_DMA_GET_REQUIRED_MASK, but according to my
>>>> grep no architecture ever sets that flag.
>>> Yes ... positive. That's the default and correct implementation based
>>> on the largest addressable physical memory.
>> Ok but still the whole thing is completely useless right now.
>
> Why? At least for aic it performs as advertised: allows the driver to
> select the most efficient descriptor format.
You were right sorry, I misread the code. Your interpretation
is correct. The interface would be correct to use for fusion,
although it should be probably extended to IOMMUs too.
-Andi
next prev parent reply other threads:[~2008-04-17 16:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-17 8:40 Query regarding modifying the DMA Mask based on the available memory in the system Prakash, Sathya
2008-04-17 8:43 ` David Miller
2008-04-17 10:06 ` Andi Kleen
2008-04-17 14:18 ` James Bottomley
2008-04-17 14:44 ` Andi Kleen
2008-04-17 15:03 ` James Bottomley
2008-04-17 15:06 ` Andi Kleen
2008-04-17 15:36 ` James Bottomley
2008-04-17 16:10 ` Andi Kleen [this message]
-- strict thread matches above, loose matches on Subject: below --
2008-04-17 17:36 Prakash, Sathya
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