On Fri, May 31, 2013 at 03:02:00AM +0200, Jens Taprogge wrote: > On Wed, May 29, 2013 at 06:08:18PM -0700, John Stultz wrote: > > On 05/29/2013 01:41 PM, Jens Taprogge wrote: > > >On Tue, May 28, 2013 at 12:51:19PM -0700, John Stultz wrote: > > >>On 05/26/2013 12:25 PM, Jens Taprogge wrote: > > >>>Hi all. > > >>> > > >>>Linux 3.9.3 hangs early during boot on a Lenovo Thinkpad X1 Carbon (Ivy > > >>>Bridge). v3.9.2 works. I have bisected the hang to > > >>> d96ac6f2: time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons. > > >>> > > >>>Reverting d96ac6f2 on top of v3.9.4 makes the kernel boot. I do not > > >>>have any additional information as the kernel hangs before anything is > > >>>displayed. The config of v3.9.4 with d96ac6f2 reverted is attached. > > >>So with 3.9.4 (nothing reverted), what was the config you were using > > >>to boot? > > >> > > >>Does changing CONFIG_RTC_HCTOSYS change the behavior? > > >> > > >>thanks > > >>-john > > >Hello John, > > > > > >turns out things behave quite differently with the patch reverted and > > >not reverted. Since there is no output, I can not tell whether I am > > >seeing one or two problems. > > > > > >With vanilla 3.9.4: > > > > > > CONFIG_RTC_HCTOSYS=y works > > > CONFIG_RTC_HCTOSYS=n does not work > > > > Huh. Strange, I actually was expecting the opposite. > > > > The odd thing is, commit d96ac6f2 *allows* HCTOSYS=y to be set. In > > other words, without that patch, HCTOSYS is always N. > > > > So its weird HCTOSYS=y works, but also reverting the patch (which > > forces HCTOSYS=N) works. > > > > Still stranger, option really shouldn't change much in early boot. > > HCTOSYS driver triggers as a late_initcall, so I'd expect you'd get > > some output before hitting trouble. > > > > > > > CONFIG_CPU_FREQ_STAT has no effect > > > > > >With d96ac6f2 reverted: > > > > > > CONFIG_CPU_FREQ_STAT=n works > > > CONFIG_CPU_FREQ_STAT=y does not work > > > > > >Please see several configurations attached. > > > > Hrm.. I do wonder if we're seeing something else going on here. > > It turns out 3.9.4 with d96ac6f2 reverted only fails with > CONFIG_CPU_FREQ_STAT=y if I manually enable the Intel PState driver by > adding the Thinkpad's IvyBridge processor to the list of supported > devices. So this is not part of the regression per se. Please forget what I said here. I switched a config option. And that made the system boot. Sorry for the confusion. So, in the case of the reverted v3.9.4 with CONFIG_CPU_FREQ_STAT=y, CONFIG_X86_VERBOSE_BOOTUP makes a difference. To update the little table from above: With d96ac6f2 reverted: CONFIG_CPU_FREQ_STAT=n works CONFIG_CPU_FREQ_STAT=y and CONFIG_X86_VERBOSE_BOOTUP=y does not work CONFIG_CPU_FREQ_STAT=y and CONFIG_X86_VERBOSE_BOOTUP=n works Please find the new working configuration attached. Best Regards, Jens
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