Messages in this thread |  | | From | Christian Vogel <> | Date | Sat, 22 Sep 2001 13:19:16 +0200 | Subject | [Newbie] Interrupt Handling and sleep/wake_up |
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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
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