• Dmitry Eremin-Solenikov's avatar
    spi: pxa2xx: toggle clocks on suspend if not disabled by runtime PM · a650b0c9
    Dmitry Eremin-Solenikov authored
    commit 2b9375b9 upstream.
    
    If PM_RUNTIME is enabled, it is easy to trigger the following backtrace
    on pxa2xx hosts:
    
    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 1 at /home/lumag/linux/arch/arm/mach-pxa/clock.c:35 clk_disable+0xa0/0xa8()
    Modules linked in:
    CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-00007-g1b3d2ee-dirty #104
    [<c000de68>] (unwind_backtrace) from [<c000c078>] (show_stack+0x10/0x14)
    [<c000c078>] (show_stack) from [<c001d75c>] (warn_slowpath_common+0x6c/0x8c)
    [<c001d75c>] (warn_slowpath_common) from [<c001d818>] (warn_slowpath_null+0x1c/0x24)
    [<c001d818>] (warn_slowpath_null) from [<c0015e80>] (clk_disable+0xa0/0xa8)
    [<c0015e80>] (clk_disable) from [<c02507f8>] (pxa2xx_spi_suspend+0x2c/0x34)
    [<c02507f8>] (pxa2xx_spi_suspend) from [<c0200360>] (platform_pm_suspend+0x2c/0x54)
    [<c0200360>] (platform_pm_suspend) from [<c0207fec>] (dpm_run_callback.isra.14+0x2c/0x74)
    [<c0207fec>] (dpm_run_callback.isra.14) from [<c0209254>] (__device_suspend+0x120/0x2f8)
    [<c0209254>] (__device_suspend) from [<c0209a94>] (dpm_suspend+0x50/0x208)
    [<c0209a94>] (dpm_suspend) from [<c00455ac>] (suspend_devices_and_enter+0x8c/0x3a0)
    [<c00455ac>] (suspend_devices_and_enter) from [<c0045ad4>] (pm_suspend+0x214/0x2a8)
    [<c0045ad4>] (pm_suspend) from [<c04b5c34>] (test_suspend+0x14c/0x1dc)
    [<c04b5c34>] (test_suspend) from [<c000880c>] (do_one_initcall+0x8c/0x1fc)
    [<c000880c>] (do_one_initcall) from [<c04aecfc>] (kernel_init_freeable+0xf4/0x1b4)
    [<c04aecfc>] (kernel_init_freeable) from [<c0378078>] (kernel_init+0x8/0xec)
    [<c0378078>] (kernel_init) from [<c0009590>] (ret_from_fork+0x14/0x24)
    ---[ end trace 46524156d8faa4f6 ]---
    
    This happens because suspend function tries to disable a clock that is
    already disabled by runtime_suspend callback. Add if
    (!pm_runtime_suspended()) checks to suspend/resume path.
    
    Fixes: 7d94a505 (spi/pxa2xx: add support for runtime PM)
    Signed-off-by: default avatarDmitry Eremin-Solenikov <dbaryshkov@gmail.com>
    Reported-by: default avatarAndrea Adami <andrea.adami@gmail.com>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    a650b0c9
spi-pxa2xx.c 34.8 KB