ARM: mxs: warnings on PM resume

[Rafael J. Wysocki]

On Saturday, June 11, 2016 03:01:31 AM Stefan Wahren wrote:
> Hi,
> 
> [add Rafael, Jörg and Jürgen to CC]
> 
> > Stefan Wahren <stefan.wahren at i2se.com> hat am 1. Juni 2016 um 22:51
> > geschrieben:
> > 
> > 
> > Hi,
> > 
> > i'm currently working on standby support for MXS platform. If i trigger the
> > standby per sysfs everything works fine, but mostly on resume i get a bunch of
> > warnings (see below for full output):
> > 
> > [   67.040000] Interrupts enabled before system core resume.
> > 
> > My current working branch [1] based on Linux 4.5 ( cmdline has
> > no_console_suspend=1 ). The test hardware is a i.MX23 board (
> > iMX233-OLinuXino-MAXI ).
> > 
> > How can i narrow down this issue to the relevant driver / interrupt ?
> > 
> > What is the right way to fix this issue?
> > 
> > I have the suspicion it's triggered by clocksource/mxs-timer.c because the
> > vendor kernel 2.6.35 had a function call [2] to suspend the timers. 
> > 
> > [1] - https://github.com/lategoodbye/linux-mxs-power/tree/rebase-4.5
> > [2] -
> > http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/arch/arm/mach-mx23/pm.c?h=imx_2.6.35_maintain#n284
> > 
> > Full output in error case:
> > 
> > # echo standby > /sys/power/state
> > [   65.820000] PM: Syncing filesystems ... done.
> > [   66.890000] Freezing user space processes ... (elapsed 0.018 seconds) done.
> > [   66.920000] Freezing remaining freezable tasks ... (elapsed 0.004 seconds)
> > done.
> > [   66.960000] smsc95xx 1-1.1:1.0 eth0: entering SUSPEND2 mode
> > [   66.990000] PM: suspend of devices complete after 56.500 msecs
> > [   67.010000] PM: late suspend of devices complete after 11.906 msecs
> > [   67.030000] PM: noirq suspend of devices complete after 12.250 msecs
> > [   67.040000] ------------[ cut here ]------------
> > [   67.040000] WARNING: CPU: 0 PID: 271 at drivers/base/syscore.c:99
> > syscore_resume+0x14c/0x1bc()
> > [   67.040000] Interrupts enabled before system core resume.
> > [   67.040000] Modules linked in: mxs_lradc(C) industrialio_triggered_buffer
> > [   67.040000] CPU: 0 PID: 271 Comm: bash Tainted: G         C
> >      4.5.0-g8b79a7d-dirty #86
> > [   67.040000] Hardware name: Freescale MXS (Device Tree)
> > [   67.040000] [<c000fdc4>] (unwind_backtrace) from [<c000de80>]
> > (show_stack+0x10/0x14)
> > [   67.040000] [<c000de80>] (show_stack) from [<c001d094>]
> > (warn_slowpath_common+0x7c/0xb4)
> > [   67.040000] [<c001d094>] (warn_slowpath_common) from [<c001d160>]
> > (warn_slowpath_fmt+0x30/0x40)
> > [   67.040000] [<c001d160>] (warn_slowpath_fmt) from [<c035c6b8>]
> > (syscore_resume+0x14c/0x1bc)
> > [   67.040000] [<c035c6b8>] (syscore_resume) from [<c005d37c>]
> > (suspend_devices_and_enter+0x480/0x770)
> > [   67.040000] [<c005d37c>] (suspend_devices_and_enter) from [<c005dad4>]
> > (pm_suspend+0x468/0x4e4)
> > [   67.040000] [<c005dad4>] (pm_suspend) from [<c005c324>]
> > (state_store+0x80/0xcc)
> > [   67.040000] [<c005c324>] (state_store) from [<c02dc0d8>]
> > (kobj_attr_store+0x18/0x1c)
> > [   67.040000] [<c02dc0d8>] (kobj_attr_store) from [<c0181988>]
> > (sysfs_kf_write+0x48/0x4c)
> > [   67.040000] [<c0181988>] (sysfs_kf_write) from [<c0180b34>]
> > (kernfs_fop_write+0xe0/0x1a0)
> > [   67.040000] [<c0180b34>] (kernfs_fop_write) from [<c0114b08>]
> > (__vfs_write+0x2c/0xe8)
> > [   67.040000] [<c0114b08>] (__vfs_write) from [<c0114c6c>]
> > (vfs_write+0xa8/0x198)
> > [   67.040000] [<c0114c6c>] (vfs_write) from [<c0114e30>]
> > (SyS_write+0x44/0x88)
> > [   67.040000] [<c0114e30>] (SyS_write) from [<c000a280>]
> > (ret_fast_syscall+0x0/0x1c)
> > [   67.040000] ---[ end trace 22f59f91777b0ede ]---
> 
> any hints or ideas to narrow down this issue are very welcome.

Interrupts should not be enabled before syscore_resume() is called, but they
are, apparently by the platform code.

Thanks,
Rafael