From: John Que
Date: Thu Jul 28 2005 - 07:46:18 EST
I want ,for tracing and debugging purposes, to be able to generate a single
interrupt on a device which (unlike the timer or ide devices, for example) does
not get interrupts very frequently.
Looking at the output of /proc/interrupts (and look at IRQ 6 of the
that the floppy device interrupt counter is not incremented during time if you
are not constatntly working with it.
So a good candidate for generating a single interrupt can be a floppy.
Is there a way to generate a single interrupt on a floppy device?
I had tried the following:
I mount the floppy;
I see that during the time, sometimes after running ls on a floppy
2 interrupts are generated; and sometimes after ls on a floppy
no interrupts are generated. The same is with
creating a file/reading a file: sometimes there
are interrupts and sometimes there are no interrupts.
So I wrote the following little program:
#define BUFFER_SIZE 2048
char buffer[BUFFER_SIZE] __attribute__((aligned(4096)));
fd = open("/dev/fd0",O_DIRECT);
if (fd < 0 )
printf("could not open device\n");
bytes_read = read(fd,buffer,512);
printf("bytes_read = %d\n",bytes_read);
Each time I ran it I got course :
bytes_read = 512
But running this program again and again ***DOES NOT*** increase the
number of interrupt on the floppy device IRQ (6).
Which user space code I should write / Which operation should I do so that each
time I will do it,(again and again) it will generate an interrupt on the
floppy IRQ (6) ?
(BTW I build this program by gcc -D_GNU_SOURCE floppy.c)
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