Comment 25 for bug 100114

OK, it seems we have identified the reason for this problem.

Willem and I worked together on tracing the value of TCSEL after resume. The code that finally pinpointed the issue was a kernel timer started in azx_resume() and stopped in azx_pcm_open() with a jiffie interval of 10, which appears to equate to 0.04 seconds. The timer writes the value of TCSEL to kern.log, so we simply look through the log for when the value of TCSEL changed from 0 to 7, and what happened in between the two timer interrupts.

It appears the cause is the 2nd CPU being brought online in the SMP kernel. We are now working on *why* this is - is it a kernel problem or something specific to the Sony Vaio or the ICH7 chipset:

[ 1630.936000] hda-intel: timer: TCSEL=0
[ 1630.944000] Calibrating delay using timer specific routine.. 3990.08 BogoMIPS (lpj=7980178)
[ 1630.944000] CPU: After generic identify, caps: bfebfbff 20100000 00000000 00000000 0000e3bd 00000000 00000001
[ 1630.944000] monitor/mwait feature present.
[ 1630.944000] CPU: L1 I cache: 32K, L1 D cache: 32K
[ 1630.944000] CPU: L2 cache: 4096K
[ 1630.944000] CPU: Physical Processor ID: 0
[ 1630.944000] CPU: Processor Core ID: 1
[ 1630.944000] CPU: After all inits, caps: bfebfbff 20100000 00000000 00003940 0000e3bd 00000000 00000001
[ 1630.944000] CPU1: Intel(R) Core(TM)2 CPU T7200 @ 2.00GHz stepping 06
[ 1630.948000] CPU1 is up
[ 1630.952000] sdb : READ CAPACITY failed.
[ 1630.952000] sdb : status=0, message=00, host=7, driver=00
[ 1630.952000] sdb : sense not available.
[ 1630.964000] sdb: Write Protect is off
[ 1630.964000] sdb: Mode Sense: 00 00 00 00
[ 1630.964000] sdb: assuming drive cache: write through
[ 1630.976000] hda-intel: timer: TCSEL=7