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Subject[Newbie] Interrupt Handling and sleep/wake_up
Hi,

-- Warning, newbie qeustion! --

currently I'm trying to write a very simple driver for the NI-GPIB-PCII
card and I'm mostly copying what was linux-gpib a long time ago.

Why am I writing to this list? I think I miss some obvious solution to a
problem. The problem lies within my handling of interrupts, let my try a
simplified example:

The board signals arrival of new data, it's ability to accept new data
or errors via the interrupt. I want my program to sleep until enough
data has been accepted or an error has occured.

Unfortunately on errors the interrupt hits just before I call
sleep_on_timeout() and because it's the only interrupt in this case
that's being generated I have to wait until sleep_on_timeout()
timeout's.

The old driver mostly uses
while(!condition && !i++>threshold)
udelay()
which I would like to avoid.

What would be the preferred way of doing this and what am I missing?

Some simple pseudocode follows to illustrate my point: bdIrq
is the interrupt-service-routine, bdDoSomething is called via
device->file-operations->read/write->... and wants to fetch something
from the card or write to it.

void bdIrq(int irq,void *data, struct pt_regs *regs){
query_board_for_status();
if( board_has_data_available )
readbuf[readcounter++]=inb(data_port);
if( board_can_accept_data )
outb(wrbuf[writecounter++],data_port);
if( board_has_error_condition_set )
board_has_error = 1;
if( buffer_full_or_end_of_data || board_has_error )
wake_up_interruptible(&irq_wqueue);
}

void bdDoSomething(){
setup_buffers_for_interrupt_routing();
tell_board_to_start_reading_or_writing();
/***** BOARD THROWS ITS INTERRUPTS HERE!!! *****/
interruptible_sleep_on_timeout(&irq_wqueue,PCIIA_SLEEP_TIMEOUT);
}

Chris

--
Is it true that cannibals won't eat clowns because they taste funny?
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