[ltp] Gen 2 (Haswell) X1 Carbon suspend to RAM hang

[Jeremy Asher]

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@Peter:

Several people [1] [2] have noted issues with Linux suspend to RAM on the
new Haswell X1 Carbon models.  I have been experiencing the issue myself on
Arch Linux running kernel 3.13.5.  In my case, the laptop appears to enter
suspend (power light starts flashing), but the fan and touch strip are
still powered up.  The display may stay powered on as well and display a
blinking cursor in console mode.  The machine is unresponsive other than
the touch strip.

I followed the general Linux PM debugging instructions [3] and noted that
with pm-trace set to core, the laptop did not freeze, but with a full
suspend, it does.  I attempted to blacklist or unload all modules on the
system from a minimal boot before entering suspend, but could not fix the
issue that way.  I eventually started disabling various modules in the BIOS
until suspend worked.  I determined that disabling either Wireless LAN or
disabling USB 3.0 mode allows the laptop to enter sleep.  I settled on
leaving USB 3.0 mode disabled for now.  I have not tried recompiling the
kernel since all relevant drivers seem to be modules.  Any thoughts?

[1]
http://ctrlx-ctrlc.blogspot.com/2014/02/installing-ubuntu-1310-on-gen-2-haswell.html
[2]
http://www.reddit.com/r/Lenovo/comments/1vmx79/i_just_bought_the_new_x1_carbon_2014_has_anyone/
[3] https://www.kernel.org/doc/Documentation/power/basic-pm-debugging.txt

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<div dir=3D"ltr"><div><div>@Peter:<br><br></div>Several people [1] [2] have=
 noted issues with Linux suspend to RAM on the new Haswell X1 Carbon models=
.=A0 I have been experiencing the issue myself on Arch Linux running kernel=
 3.13.5.=A0 In my case, the laptop appears to enter suspend (power light st=
arts flashing), but the fan and touch strip are still powered up.=A0 The di=
splay may stay powered on as well and display a blinking cursor in console =
mode.=A0 The machine is unresponsive other than the touch strip.<br>
<br>I followed the general Linux PM debugging instructions [3] and noted th=
at with pm-trace set to core, the laptop did not freeze, but with a full su=
spend, it does.=A0 I attempted to blacklist or unload all modules on the sy=
stem from a minimal boot before entering suspend, but could not fix the iss=
ue that way.=A0 I eventually started disabling various modules in the BIOS =
until suspend worked.=A0 I determined that disabling either Wireless LAN or=
 disabling USB 3.0 mode allows the laptop to enter sleep.=A0 I settled on l=
eaving USB 3.0 mode disabled for now.=A0 I have not tried recompiling the k=
ernel since all relevant drivers seem to be modules.=A0 Any thoughts?<br>
<br>[1] <a href=3D"http://ctrlx-ctrlc.blogspot.com/2014/02/installing-ubunt=
u-1310-on-gen-2-haswell.html">http://ctrlx-ctrlc.blogspot.com/2014/02/insta=
lling-ubuntu-1310-on-gen-2-haswell.html</a><br>[2] <a href=3D"http://www.re=
ddit.com/r/Lenovo/comments/1vmx79/i_just_bought_the_new_x1_carbon_2014_has_=
anyone/">http://www.reddit.com/r/Lenovo/comments/1vmx79/i_just_bought_the_n=
ew_x1_carbon_2014_has_anyone/</a><br>
[3] <a href=3D"https://www.kernel.org/doc/Documentation/power/basic-pm-debu=
gging.txt">https://www.kernel.org/doc/Documentation/power/basic-pm-debuggin=
g.txt</a><br><br></div><div><div><div><br></div></div></div></div>

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