How ?

How ?

[Rakesh Jagota]

Hi all,

 Can anyone suggest me how we can invoke the interrupt generated in the
kernel from the user application. I am getting the interrupt in the driver, I
want to update some register in the application, when the inettrupt will be
generated, Right now I am using polloing method. Continuously I am calling
read routines.

Thanks in advance,

Rakesh Jagota


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Re: How ?

[Bret Indrelee]

On Thu, 15 May 2003, Rakesh Jagota wrote:
>  Can anyone suggest me how we can invoke the interrupt generated in the
> kernel from the user application. I am getting the interrupt in the driver, I
> want to update some register in the application, when the inettrupt will be
> generated, Right now I am using polloing method. Continuously I am calling
> read routines.

Don't know why you want to handle it from user space, but the easiest way
to notify an application would be to send a signal. Have a special ioctl()
to notify the driver that this application wants a signal, and then when
the driver receives the interrupt it clears the condition and sends a
signal to the registered application(s).

-Bret

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Bret Indrelee                 QLogic Corporation
Bret.Indrelee@qlogic.com      6321 Bury Drive, St 13, Eden Prairie, MN 55346


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Re: How ?

[Wolfgang Denk]

In message <Pine.LNX.4.44.0305150828210.26702-100000@spider.ancor.com> you wrote:
>
> Don't know why you want to handle it from user space, but the easiest way
> to notify an application would be to send a signal. Have a special ioctl()
> to notify the driver that this application wants a signal, and then when
> the driver receives the interrupt it clears the condition and sends a
> signal to the registered application(s).

Instead of inventing new special ioctl()'s it's  probably  better  to
use existing and standardized interfaces like select() resp. poll().

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
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failed to start because of the following error: The operation comple-
ted successfully."                         -- Windows NT Server v3.51

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RE: How?

[Craig Hollabaugh]

Rakesh,


Your interrupt routine can send a signal to your user space process.

Here's what I've used

void sendSignal(void)
{
        struct task_struct *p;
        if ( pid ) {

/*
        for_each_task(p) {
                if (p->pid == pid) {
                        send_sig(SIGIO,p,1);
                        break;
                }
        }
*/

/* or better yet */

        if (p = find_task_by_pid(pid)) send_sig(SIGIO,p,1);
        /* from page 83 in ulk */
        }
}

ulk is Understanding The Linux Kernel.

Craig


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___________________________________________________________
Dr. Craig Hollabaugh                   craig@hollabaugh.com
Author of Embedded Linux

P.O. Box 1405
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970 325 4810 home            www.hollabaugh.com/resume.html
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