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Re: 4.0/i386 auich_calibrate() and GENERIC.NOACPI failure
On Sat, Jan 12, 2008 at 05:16:53PM +0000, Andrew Doran wrote:
> > 1. splvm() didn't help
> > 2. splclock() _did_ fix the problem!
> > 3. the value of curcpu()->ci_ilevel is 0 (zero) before the loop.
> > Are you sure we are supposed to be at IPL_HIGH? I thought zero
> > was IPL_NONE?
> It's a misfeature but most of autoconf should happen with interrupts off.
> Something is dropping the spl - perhaps an "avoid uninitialized variable
> warning" commit at some point? I'll see if I can find it. It looks like the
> bug in kern_tc.c was masking that. But I guess the auich calibration loop
> should be wrapped in splhigh()/splx() or be a bit smarter so that it doesn't
> need to rely on interrupts being blocked.
Hmm. The auich_calibrate() loop is being called from
config_process_deferred(). If you believe the comments
in subr_autoconf.c, interrupts are supposed to be enabled
In fact, I added the following printfs to subr_autoconf.c:
* Do the machine-dependent portion of autoconfiguration. This
* sets the configuration machinery here in motion by "finding"
* the root bus. When this function returns, we expect interrupts
* to be enabled.
printf("auich: BEFORE cpu_configure %#x\n", curcpu()->ci_ilevel);
printf("auich: AFTER cpu_configure %#x\n", curcpu()->ci_ilevel);
* Now that we've found all the hardware, start the real time
* and statistics clocks.
printf("auich: AFTER initclocks %#x\n", curcpu()->ci_ilevel);
cold = 0; /* clocks are running, we're warm now! */
* Now callback to finish configuration for devices which want
* to do this once interrupts are enabled.
printf("auich: AFTER after DEffered %#x\n", curcpu()->ci_ilevel);
this results in (note that my old splvm() patch is still in there):
auich: BEFORE cpu_configure 0xe
auich0 at pci0 dev 31 function 5: i82801BA (ICH2) AC-97 Audio
auich0: interrupting at irq 10
auich0: ac97: Analog Devices AD1885 codec; headphone, Analog Devices Phat Stereo
auich0: ac97: ext id 1<VRA>
auich: AFTER cpu_configure 0
auich: AFTER initclocks 0
auich: BEFORE SPL 0
auich: AFTER SPL 0xa
auich0: measured ac97 link rate at 47007 Hz, will use 48000 Hz
audio0 at auich0: full duplex, mmap, independent
auich: AFTER after DEffered 0
The other thing I was wondering was if fix this by putting splhigh()
in auich.c. Will that spl block microtime() from advancing with some
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