Hi all...
since some time ago I have noticed that mplayer can't use the RTC for
time accounting. Perhaps it is deprecated and should be migrated to
hrtimers, that is what every reference I found said, but the fact is
that nowadays it uses it.
I thought I was because a misbuild of my kernel, but now I have just
built a 2.6.24.2 with every rtc modular to test them (in my case,
just rtc, genrtc and rtc-cmos - I'm not aware of any other that can
work on my mobo, ICH5/i875P).
I use a trimmed down version of the test in Documentacion/rtc.txt.
Results vary:
genrtc fails
crw-r--r-- 1 root root 10, 135 Feb 21 00:53 /dev/rtc
Using /dev/rtc
RTC_IRQP_READ ioctl: Invalid argument
rtc works
crw-r--r-- 1 root root 10, 135 Feb 21 00:53 /dev/rtc
Using /dev/rtc
Initial PI rate: 1024Hz
2 Hz: ..........
4 Hz: ..........
8 Hz: ..........
16 Hz: ..........
32 Hz: ..........
64 Hz: ..........
Device or resource busy
and rtc-cmos behaves strangely. After modprobe, even when /dev/rtc*
are already present, I have to wait even 5 seconds to not have a 'Device or
resource busy' error on open(). And when it opens it just gets stuck
after the first dot:
Using /dev/rtc
Initial PI rate: 1024Hz
2 Hz: .
The loop is
for (i=0; i<10; i++)
{
res = read(rtc,&data,sizeof(unsigned long));
if (res<0)
{
perror("read");
exit(errno);
}
printf(".");
fflush(stdout);
}
They all give different info in /proc/driver/rtc and
/proc/sys/dev/rtc/max-user-freq:
genrtc
crw-r--r-- 1 root root 10, 135 Feb 21 01:03 /dev/rtc
rtc_time : 00:03:25
rtc_date : 2008-02-21
rtc_epoch : 1900
alarm : 00:00:00
DST_enable : no
BCD : yes
24hr : yes
square_wave : no
alarm_IRQ : no
update_IRQ : no
periodic_IRQ : no
periodic_freq : 0
batt_status : okay
cat: /proc/sys/dev/rtc/max-user-freq: No such file or directory
rtc
crw-r--r-- 1 root root 10, 135 Feb 21 01:03 /dev/rtc
rtc_time : 00:03:26
rtc_date : 2008-02-21
rtc_epoch : 1900
alarm : **:00:10
DST_enable : no
BCD : yes
24hr : yes
square_wave : no
alarm_IRQ : no
update_IRQ : no
periodic_IRQ : no
periodic_freq : 1024
batt_status : okay
64
rtc-cmos
lrwxrwxrwx 1 root root 4 Feb 21 01:03 /dev/rtc -> rtc0
crw-r--r-- 1 root root 254, 0 Feb 21 01:03 /dev/rtc0
rtc_time : 00:03:39
rtc_date : 2008-02-21
alrm_time : **:00:10
alrm_date : ****-**-**
alarm_IRQ : no
alrm_pending : no
24hr : yes
periodic_IRQ : no
update_IRQ : yes
DST_enable : no
periodic_freq : 1024
batt_status : okay
cat: /proc/sys/dev/rtc/max-user-freq: No such file or directory
So all of them are not completely interchangeable, the only one that works
as expected is 'rtc'.
What am I doing wrong ? Or is it a bug ?
--
J.A. Magallon <jamagallon()ono!com> \ Software is like sex:
\ It's better when it's free
Mandriva Linux release 2008.1 (Cooker) for i586
Linux 2.6.23-jam05 (gcc 4.2.2 20071128 (4.2.2-2mdv2008.1)) SMP PREEMPT