From: Jaap-Jan Boor <jjboor@aimsys•nl>
To: Dan Malek <dan@embeddededge•com>
Cc: Juergen Oberhofer <e9826367@student•tuwien.ac.at>,
linuxppc-embedded@lists•linuxppc.org
Subject: Re: mpc / linux kernel - user space
Date: Mon, 01 Dec 2003 09:18:55 +0100 [thread overview]
Message-ID: <1070266735.328.5.camel@linpc003.aimsys.nl> (raw)
In-Reply-To: <3FC76CEA.9040309@embeddededge.com>
On Fri, 2003-11-28 at 16:42, Dan Malek wrote:
> Jaap-Jan Boor wrote:
>
> > If you want to send a signal to user code, you can use kill_proc()
> > I think.
>
> IMHO, trying to use signals to propagate a hardware interrupt to a
> user application is complicated and has design flaws (what happens
> if the application "misses" an interrupt or gets blocked for some
> reason).
Fortunately I never used it (that's the 'I think')
>
> A couple of other methods that I find simple and use extensively
> are multi-threading the application and then using a different
> minor ID device to wait on a read() or ioctl() to simply return.
> The driver just uses the standard sleep/wakeup mechanisms to
> synchronize with the application.
>
> Another, and I think most useful, method is to implement a select/poll
> entry point in the driver. It provides the most flexibility when
> waiting for various events, plus provides a timeout should something
> fail to function properly.
Yes, especially the timeout is nice as 'this should never happen'
failures never happens except with the customer
Jaap-Jan
>
>
> -- Dan
>
>
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2003-12-01 8:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-27 16:07 mpc / linux kernel - user space Juergen Oberhofer
2003-11-27 17:38 ` Jaap-Jan Boor
2003-11-27 18:08 ` Juergen Oberhofer
2003-11-27 19:28 ` Dan Kegel
2003-11-28 4:30 ` How to change /proc to the writable directory John Zhou
2003-11-28 8:12 ` Wolfgang Denk
2003-11-28 9:16 ` mpc / linux kernel - user space Jaap-Jan Boor
2003-11-28 15:42 ` Dan Malek
2003-12-01 8:18 ` Jaap-Jan Boor [this message]
2003-12-01 12:51 ` Peripherals Memory Mapping Kevin A. Sapp
2003-12-14 15:28 ` Paul Miller
2003-12-01 13:47 ` mpc / linux kernel - user space Juergen Oberhofer
2003-11-28 5:34 ` Sampath Kumar
2003-11-28 8:14 ` Wolfgang Denk
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