Messages in this thread | | | Date | Wed, 13 Aug 2008 17:18:27 +0200 | From | Ingo Molnar <> | Subject | Re: [git pull] ftrace for v2.6.27 |
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* Steven Rostedt <srostedt@redhat.com> wrote:
> Bruce Duncan wrote: >> Hi Ingo, Steven, everyone, >> >> [ Please CC me in replies ] >> >> I have just tracked down a regression in 2.6.27-rc2 wrt 2.6.26. Commit >> 77a2b37d227483fe52aead242652aee406c25bf0 (ftrace: startup tester on >> dynamic tracing.) causes my laptop to fail to resume from S3 (it simply >> reboots about a second after the resume starts and the display never >> shows anything). >> >> The patch doesn't revert with patch -R (I don't know if there's a >> cleverer way to ask git to revert it), but the problem goes away if I >> turn off CONFIG_DYNAMIC_FTRACE. >> >> The commit and bisect log are attached. Please can you help me to debug this? >> >> >> > > I found that I have a box that displays this bug. Without FTRACE it > suspends and resumes fine. With FTRACE enabled, it does not. > > I'll be actively debugging it now. (unfortunately, as with all new > laptops, I don't have a serial for it).
try latest tip/master plus an USB debug key, then enable CONFIG_EARLY_PRINTK_DBGP=y in your .config on the host, add the earlyprintk=dbgp,keep boot parameter and reboot [and disable USB for good measure]. On the other host you connect to via an USB cable, enable USB_SERIAL_DEBUG=y and use /dev/ttyUSB0 with the serial terminal app of your choice.
that, as long as the USB ports are operational, gives a working serial console on just about any laptop.
Ingo
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