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how can i send real-time signal?

DISCUSSION wael showair 2 participants 3 messages Jun 5, 2009 – Jun 7, 2009

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#0 lore raw

Hi All,
i m using linux-kernel 2.6.27 & a board of MPC8555 processor. i have also DSP-core on the same board.

My aim is : Each time the DSP-core interrupts the MPC8555 processor, a process in the user space will be informed by the arrival of this each interrupt.

So i decided to use sw signals, in the ISR of the DSP-core interrupt i send a SW signal to the user space process? Is this the best solution? are there any better suggestion to achieve my aim?

i used the kernel API send_sig_info because i want to send information with the sent signal & my signal type was SIGUSR1

i could receive the SW signal successfully but i found out that the standard SW signals are not queued if they r in the pending queue of the user space process but the real-time signals do.
so i changed the type of the signal to SIGRTMIN but unfortunately i could receive any SW signal from my ISR & i noticed that always the second interrupt causes a kernel panic

so am i using the correct signal type?
am i using the correct kernel API to send a real-time SW signal?

plz help

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#1 lore raw

Am Fri, 5 Jun 2009 10:41:56 -0700 (PDT)
schrieb wael showair <[email protected]>:

Quoted 3 lines

My aim is : Each time the DSP-core interrupts the MPC8555 processor, a process in the user space will be informed by the arrival of this each interrupt.

You should have a look at drivers/uio...

Quoted 3 lines

So i decided to use sw signals, in the ISR of the DSP-core interrupt i send a SW signal to the user space process? Is this the best solution? are there any better suggestion to achieve my aim?

signals are expensive. Look at the UIO-Framework for a cheaper solution. preallocated RT-Signals on the other Hand are fragile. Blocking reads are cheaper and in case of preempt-RT, but not resticted to it, much easier to handle.

Bene

#2 lore raw
In reply to wael showair

Am Fri, 5 Jun 2009 10:41:56 -0700 (PDT)
schrieb wael showair <[email protected]>:

Quoted 3 lines

My aim is : Each time the DSP-core interrupts the MPC8555 processor, a process in the user space will be informed by the arrival of this each interrupt.

You should have a look at drivers/uio...

Quoted 3 lines

So i decided to use sw signals, in the ISR of the DSP-core interrupt i send a SW signal to the user space process? Is this the best solution? are there any better suggestion to achieve my aim?

signals are expensive. Look at the UIO-Framework for a cheaper solution. preallocated RT-Signals on the other Hand are fragile. Blocking reads are cheaper and in case of preempt-RT, but not resticted to it, much easier to handle.

Bene

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