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Message-ID: <4A5F3975.70503@s5r6.in-berlin.de>
Date: Thu, 16 Jul 2009 16:30:13 +0200
From: Stefan Richter <stefanr@...6.in-berlin.de>
To: Matthew Garrett <mjg@...hat.com>
CC: linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
linux-ide@...r.kernel.org
Subject: Re: [PATCH 1/4] scsi: Allow hosts to be flagged as hotpluggable
Matthew Garrett wrote:
> Userspace may wish to make policy decisions based on whether a host
> supports device hotplug or not - for example, AHCI link power management
> disables hotplug, so may only be desirable on hotplug ports. Add
> support for marking hosts as hotpluggable in order to allow userspace to
> treat them appropriately.
[...]
> --- a/include/scsi/scsi_host.h
> +++ b/include/scsi/scsi_host.h
> @@ -421,6 +421,7 @@ struct scsi_host_template {
> */
> unsigned unchecked_isa_dma:1;
>
> +
> /*
> * True if this host adapter can make good use of clustering.
> * I originally thought that if the tablesize was large that it
> @@ -447,6 +448,11 @@ struct scsi_host_template {
> unsigned ordered_tag:1;
>
> /*
> + * True if host supports hotplugging
> + */
> + unsigned hotpluggable:1;
> +
The comment should specify what the actual effects of the flag are.
(Provides the default for Scsi_Host.hotpluggable?)
> + /*
> * Countdown for host blocking with no commands outstanding.
> */
> unsigned int max_host_blocked;
> @@ -622,6 +628,9 @@ struct Scsi_Host {
> /* Asynchronous scan in progress */
> unsigned async_scan:1;
>
> + /* 1 if hotpluggable, 0 if not */
> + unsigned hotpluggable:1;
> +
Ditto here.
(Is used by power management infrastructure to decide over runtime PM
policy? I.e. don't enter power states which would prevent the port from
detecting/ reporting hotplug events?)
> /*
> * Optional work queue to be utilized by the transport
> */
--
Stefan Richter
-=====-==--= -=== =----
http://arcgraph.de/sr/
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