fasync (Async Notification)
From: Vijay Nikam <hidden>
Date: 2009-03-09 06:33:28
Hello All, I have mpc8313erdb eval board and kernel 2..6.20 on it. I have written GPIO driver and have enabled Async Notification (SIGIO) In the driver I am generating interrupt whenever the status of GPIO pin (GPIO 2) changes, this part is working correct (as soon as the GPIO pin status changes the interrupt is generated). Then I included Async Notification to notify the particluar user space process (to the process which I want to) by using fasync method, kill_fasync is called in Interrupt handler and also the kill_fasync signals the particular process and the Signal handler executes and says SIGIO is received. But the problem is, if I change GPIO pin status twice then two interrupts are generated but I get SIGIO Async Notification only once. Whereras I am expecting that I should get twice SIGIO Async Notification (Theory says the same). Could anyone please let me what is the reason for this ? ? ? Kindly please acknowledge ... thank you ... Kind Regards, Vijay Nikam