[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] Timer/clock for Linux
From: |
NyOS |
Subject: |
Re: [Qemu-devel] [PATCH] Timer/clock for Linux |
Date: |
Tue, 25 Apr 2006 13:04:45 +0200 |
User-agent: |
Opera M2/8.52 (Linux, build 1631) |
On Mon, 24 Apr 2006 23:41:23 +0200, Fabrice Bellard <address@hidden>
wrote:
Hi,
Can other people confirm that it is better to always use /dev/rtc on
Linux ? Is there a way to get the real resolution of the host timer ?
Fabrice.
Hi!
There must be one.
Mplayer says this after setting /proc/sys/dev/rtc/max-user-freq below 1024:
Linux RTC init error in ioctl (rtc_irqp_set 1024): Permission denied
Try adding "echo 1024 > /proc/sys/dev/rtc/max-user-freq" to your system
startup scripts.
Using nanosleep() timing
URL=http://mplayerhq.hu/homepage/design7/dload.html
this code can be found in mplayer.c file aprox. 1100th line:
#ifdef HAVE_RTC
if(!nortc)
{
// seteuid(0); /* Can't hurt to try to get root here */
if ((rtc_fd = open(rtc_device ? rtc_device : "/dev/rtc", O_RDONLY)) <
0)
mp_msg(MSGT_CPLAYER, MSGL_WARN, "Failed to open %s: %s (it should be
readable by the user.)\n",
rtc_device ? rtc_device : "/dev/rtc", strerror(errno));
else {
unsigned long irqp = 1024; /* 512 seemed OK. 128 is jerky. */
if (ioctl(rtc_fd, RTC_IRQP_SET, irqp) < 0) {
mp_msg(MSGT_CPLAYER, MSGL_WARN, "Linux RTC init error in ioctl
(rtc_irqp_set %lu): %s\n", irqp, strerror(errno));
mp_msg(MSGT_CPLAYER, MSGL_HINT, "Try adding \"echo %lu >
/proc/sys/dev/rtc/max-user-freq\" to your system startup scripts.\n",
irqp);
close (rtc_fd);
rtc_fd = -1;
} else if (ioctl(rtc_fd, RTC_PIE_ON, 0) < 0) {
/* variable only by the root */
mp_msg(MSGT_CPLAYER, MSGL_ERR, "Linux RTC init error in ioctl
(rtc_pie_on): %s\n", strerror(errno));
close (rtc_fd);
rtc_fd = -1;
} else
mp_msg(MSGT_CPLAYER, MSGL_INFO, MSGTR_UsingRTCTiming, irqp);
}
}
I've never used RTC in my programs, but ioctl seems to return negative
value on such an error. A hint like that can also be good on startup.
Miklos Gyozo (Nyos)
- [Qemu-devel] [PATCH] Timer/clock for Linux, Kazu, 2006/04/11
- Message not available
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Fabrice Bellard, 2006/04/24
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Jamie Lokier, 2006/04/24
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Fabrice Bellard, 2006/04/25
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Jamie Lokier, 2006/04/25
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Paul Brook, 2006/04/25
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Jamie Lokier, 2006/04/26
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Paul Brook, 2006/04/26
- Re: [Qemu-devel] [PATCH] Timer/clock for Linux, Jamie Lokier, 2006/04/26
Re: [Qemu-devel] [PATCH] Timer/clock for Linux,
NyOS <=