Hello,
I'm using a RISCStation board with ARM Linux 2.2.17, and am having
problems using the Real Time Clock. I wanted to run a routine roughly
every second, and rather than continually polling gettimeofday() I
thought I could use the RTC (like it says in
linux/Documentation/rtc.txt). However although I can read the time from
it using ioctls, and doing things like 'cat /proc/rtc' and 'cat
/proc/interrupts' provide appropriate responses, the clock doesn't
appear to generate any interrupts. This means that when I call read(),
the program blocks forever.
Can anyone tell me what's going on here, or point me in the direction of
the file I need to fix?
Thanks in advance...
Chris West
[EMAIL PROTECTED]
PS. I've included a snippet from the code I'm using (just in case). It
works fine on my i386-pc-linux-gnu box, but blocks forever at the read()
call on the ARM.
...
int io_status, rtc;
unsigned long r_data;
fd_set read_rtc;
struct timeval timeout = { 0, 0 };
rtc = open( "/dev/rtc", O_RDONLY );
if( rtc == -1 ) exit(1);
io_status = ioctl( rtc, RTC_UIE_ON, 0 );
if( io_status == -1 ) exit(1);
...
while( running ) {
FD_ZERO( &read_rtc );
FD_SET( rtc, &read_rtc );
cerr << "selecting rtc..." << flush;
io_status = select( rtc+1, &read_rtc, NULL, NULL, &timeout );
if( io_status == -1 ) break;
cerr << "reading rtc..." << flush;
io_status = read( rtc, &r_data, sizeof(unsigned long) );
if( io_status == -1 ) break;
[ do stuff ]
};
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