Bug 2478
| Summary: | system noise when using ACPI -- HP nx7000 | ||
|---|---|---|---|
| Product: | ACPI | Reporter: | Steffen Hein (bugzilla) |
| Component: | Power-Processor | Assignee: | Zhu Yi (yi.zhu) |
| Status: | REJECTED DUPLICATE | ||
| Severity: | normal | CC: | burcin, lowe, yi.zhu |
| Priority: | P2 | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Kernel Version: | Kernel 2.6 series (still exists in 2.6.5) | Subsystem: | |
| Regression: | --- | Bisected commit-id: | |
|
Description
Steffen Hein
2004-04-08 15:06:23 UTC
Do you know whether the sound is from the CPU fan? Does it also happen on recent 2.6.6 (2.6.7-rc2) kernel? Does it happen if you stop Intel SpeedStep software in "the other OS"? I can confirm a high pitched noise using the 2.6.6-1.397 Arjan kernel under ACPI using a Dell Inspiron 4150 with a Pentium 4 Mobile 1.6 GHz. This is not coming from the fan, rather the noise seems identical to the APM idle noise. According to the kernel mailing lists, this is produced by the new 1kHz clock speed of the 2.6 kernel. If I boot using apm=on apm=idle-threshold=100 the noise disappears. I have checked this makes no difference to power consumption and thermal properties of my system. Likewise the noise was not present under the 2.4 kernels. I don't know how to turn the noise off under ACPI. > Do you know whether the sound is from the CPU fan? It's *definitely* not the CPU fan. It sounds a bit like the high-pitched tone, some old TVs and CRTs make. > Does it also happen on recent 2.6.6 (2.6.7-rc2) kernel? I'm now using a 2.6.6 kernel but with the C3 powerstate disabled because the centrino wlan driver doesn't like it (using the small patch from ipw2100.sf.net). No noise with that configuration! I'll try a vanilla 2.6.7 kernel when it's released. > Does it happen if you stop Intel SpeedStep software in "the other OS"? No 2.6.7 was released. How is it going? Still happens on a vanilla 2.6.7 kernel. Does set HZ to 100 help? --- linux-2.6.7/include/asm-i386/param.h 2004-06-17 09:34:28.000000000 +0800 +++ linux-2.6.7-new/include/asm-i386/param.h 2004-07-19 13:30:54.207125536 +0800 @@ -2,7 +2,7 @@ #define _ASMi386_PARAM_H #ifdef __KERNEL__ -# define HZ 1000 /* Internal kernel timer frequency */ +# define HZ 100 /* Internal kernel timer frequency */ # define USER_HZ 100 /* .. some user interfaces are in "ticks" */ # define CLOCKS_PER_SEC (USER_HZ) /* like times() */ #endif This seems to help. The noise disappeared. David Lowe: Can you confirm this? I am no longer able to get my machine to make the same noise under ACPI. I recall previously my machine loaded the "thermal" and "processor" kernel modules. However after an update (I'm now using Fedora Core 2), these modules are no longer there, and seem to have been replaced by asus_acpi, for me. There is still a faint continuous high-pitched whine, but it is also present under Windows XP, so I assume its something different, and regard this as a fix. Under APM the noise is still there, turning on and off dependent on processor load, so I am still using the apm=idle-threshold=100 boot parameter. I also get the same noise on an HP nx7000 1500MHz Centrino, it is still there with 2.6.8.1. The noise seems to be connected to the cpu frequency and system load. If the load is high, and the cpu is working at a high frequency, the noise stops, when the load gets low again, the noise comes back. Under low system load, lowering the cpu speed with cpufreq also stops the noise. Setting HZ to 100 as in comment 6 solves the problem altogether. note: FC2 includes the processor module as part of the kernel, which is why you can't unload it. Others have reported noise when their 2.6 system enters C3 power saving state in idle. It is good to know that HZ=100 also addresses the issue. You can observe C3 usage in /proc/acpi/processor/CPU0/power You can prevent C3 usage by plugging in a USB mouse, as this causes bus master activity that prevents entering C3. You could also run a low priority "cycle soaker" to make your system never enter idle, and see if that makes the noise go away. There are also a couple of ways to disable just C3 in the latest kernel -- see bug 3549. closing as a duplicate of 3406 "c3 causes noise". Please re-open if disabling C3 doesn't fix it. *** This bug has been marked as a duplicate of 3406 *** |