• Sudeep Holla's avatar
    drivers: cpuidle: Don't initialize big.LITTLE driver if MCPM is unavailable · 194fe6f2
    Sudeep Holla authored
    If big.LITTLE driver is initialized even when MCPM is unavailable,
    we get the below warning the first time cpu tries to enter deeper
    C-states.
    
    ------------[ cut here ]------------
    WARNING: CPU: 4 PID: 0 at kernel/arch/arm/common/mcpm_entry.c:130 mcpm_cpu_suspend+0x6d/0x74()
    Modules linked in:
    CPU: 4 PID: 0 Comm: swapper/4 Not tainted 3.19.0-rc3-00007-gaf5a2cb1ad5c-dirty #11
    Hardware name: ARM-Versatile Express
    [<c0013fa5>] (unwind_backtrace) from [<c001084d>] (show_stack+0x11/0x14)
    [<c001084d>] (show_stack) from [<c04fe7f1>] (dump_stack+0x6d/0x78)
    [<c04fe7f1>] (dump_stack) from [<c0020645>] (warn_slowpath_common+0x69/0x90)
    [<c0020645>] (warn_slowpath_common) from [<c00206db>] (warn_slowpath_null+0x17/0x1c)
    [<c00206db>] (warn_slowpath_null) from [<c001cbdd>] (mcpm_cpu_suspend+0x6d/0x74)
    [<c001cbdd>] (mcpm_cpu_suspend) from [<c03c6919>] (bl_powerdown_finisher+0x21/0x24)
    [<c03c6919>] (bl_powerdown_finisher) from [<c001218d>] (cpu_suspend_abort+0x1/0x14)
    [<c001218d>] (cpu_suspend_abort) from [<00000000>] (  (null))
    ---[ end trace d098e3fd00000008 ]---
    
    This patch fixes the issue by checking for the availability of MCPM
    before initializing the big.LITTLE cpuidle driver
    Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
    Acked-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
    Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
    Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
    194fe6f2
cpuidle-big_little.c 6.8 KB