Bug 113351

Summary:	i7-6500U CPU on Thinkpad X1 Yoga does not boot without intel_pstate=no_hwp
Product:	Power Management	Reporter:	Mario Geiger (geiger.mario)
Component:	intel_pstate	Assignee:	Chen Yu (yu.c.chen)
Status:	CLOSED DUPLICATE
Severity:	normal	CC:	jacek, kernel.org, lenb, lubko+kernel, rui.zhang, srinivas.pandruvada, yu.c.chen
Priority:	P1
Hardware:	Intel
OS:	Linux
Kernel Version:	4.4	Subsystem:
Regression:	No	Bisected commit-id:

Description Mario Geiger 2016-02-27 22:51:04 UTC

Does not boot until I put GRUB_CMDLINE_LINUX="intel_pstate=no_hwp" for grub parameter.

Comment 1 Jacek Bajor 2016-02-28 13:43:31 UTC

I am experiencing the same issue with kernel 4.5.0.rc4.

Comment 2 Chen Yu 2016-02-29 02:42:06 UTC

could you please test with:
boot kernel with intel_pstate=no_hwp


# modprobe msr

# rdmsr 0x770
0
# wrmsr 0x773 0
# rdmsr 0x773

# wrmsr ox770 1 

does it hang?

I suspect this is related to 
https://bugzilla.kernel.org/show_bug.cgi?id=110941

Comment 3 Jacek Bajor 2016-02-29 12:59:35 UTC

The machine did not hang right after executing command, but froze completely a minute later when I pressed the mute button.

Comment 4 Mario Geiger 2016-02-29 13:38:55 UTC

# modprobe msr
# rdmsr 0x770
0
# wrmsr 0x773 0
# rdmsr 0x773
0
# wrmsr 0x770 1 
[hang immediately]

Comment 5 Srinivas Pandruvada 2016-03-01 17:16:52 UTC

Can you try to boot with idle=nomwait and see if you can boot (without intel_pstate=no_hwp or intel_pstate=disable)?

Comment 6 Jacek Bajor 2016-03-02 00:11:12 UTC

I could not boot with idle=nomwait option.

Comment 7 Lubko 2016-03-09 10:27:04 UTC

most likely a duplicate of #110941
https://bugzilla.kernel.org/show_bug.cgi?id=110941

Comment 8 Chen Yu 2016-03-15 06:54:10 UTC


*** This bug has been marked as a duplicate of bug 110941 ***