Re: [patch 0/7] Asynchronous Notification for ATAPI devices (v2) -resend

From: Kristen Carlson Accardi
Date: Fri May 04 2007 - 16:39:43 EST


On Fri, 04 May 2007 15:30:03 -0500
James Bottomley <James.Bottomley@xxxxxxxxxxxx> wrote:

> On Fri, 2007-05-04 at 11:12 -0700, Kristen Carlson Accardi wrote:
> > This patch series implements Asynchronous Notification (AN) for SATA
> > ATAPI devices as defined in SATA 2.5 and AHCI 1.1 and higher. Drives
> > which support this feature will send a notification when new media is
> > inserted and removed, preventing the need for user space to poll for
> > new media. This support is exposed to user space via a flag that will
> > be set in /sys/block/sr*/capability_flags. If the flag is set, user
> > space can disable polling for the new media, and the genhd driver will
> > send a KOBJ_CHANGE event with the envp set to MEDIA_CHANGE_EVENT=1.
> >
> > Note that this patch only implements support for directly attached
> > drives - AN with drives attached to a port multiplier requires
> > additional changes.
>
> I seem to remember when this came up before, the observation was made
> that AENs occur for many more things than simple media change notices,
> so we should probably have a more generic AEN handling mechanism. Is
> there any plan to move in this direction
>
> James
>
In this implementation, we use kobject_uevent_env (vs. just
kobject_uevent in the original implementation) to send a KOBJ_CHANGE
with the enviroment value of MEDIA_CHANGE=1. For other asynchronous
events, you could still use KOBJ_CHANGE with a different env value.
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