From: Helge Hafting <helge.hafting@hist.no>
To: Davide Rossetti <davide.rossetti@roma1.infn.it>
Cc: linux-kernel@vger.kernel.org
Subject: Re: MSI to memory?
Date: Wed, 07 Jul 2004 14:45:47 +0200 [thread overview]
Message-ID: <40EBF07B.8040003@hist.no> (raw)
In-Reply-To: <40EBED33.3050707@roma1.infn.it>
Davide Rossetti wrote:
> Rajesh Shah wrote:
>
>> What type of usage model did you have in mind to have the
>>
>> device write to memory instead of using MSI for interrupts?
>>
>>
> for instance for a fast wake-up trick. the driver loops on a memory
> location until the MSI write access changes the memory content...
Won't that put a bad load on the bus? Someone else might need it:
* Another cpu in a smp system
* Any device doing bus-master transfers, even in a UP system
That polling loop had better be guaranteed to be _very_ short.
Helge Hafting
next prev parent reply other threads:[~2004-07-07 12:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-01 18:15 MSI to memory? Bjorn Helgaas
2004-07-01 18:53 ` Rajesh Shah
2004-07-02 15:51 ` Bjorn Helgaas
2004-07-07 12:31 ` Davide Rossetti
2004-07-07 12:45 ` Helge Hafting [this message]
2004-07-07 16:59 ` Roland Dreier
2004-07-08 9:03 ` Helge Hafting
2004-07-07 17:04 ` Zwane Mwaikambo
2004-07-07 13:15 ` Richard B. Johnson
2004-07-07 17:13 ` Rajesh Shah
2004-07-02 16:04 ` Roland Dreier
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