• Hans de Goede's avatar
    misc: lis3lv02d_i2c: Fix regulators getting en-/dis-abled twice on suspend/resume · ac3e0384
    Hans de Goede authored
    When not configured for wakeup lis3lv02d_i2c_suspend() will call
    lis3lv02d_poweroff() even if the device has already been turned off
    by the runtime-suspend handler and if configured for wakeup and
    the device is runtime-suspended at this point then it is not turned
    back on to serve as a wakeup source.
    
    Before commit b1b9f7a4 ("misc: lis3lv02d_i2c: Add missing setting
    of the reg_ctrl callback"), lis3lv02d_poweroff() failed to disable
    the regulators which as a side effect made calling poweroff() twice ok.
    
    Now that poweroff() correctly disables the regulators, doing this twice
    triggers a WARN() in the regulator core:
    
    unbalanced disables for regulator-dummy
    WARNING: CPU: 1 PID: 92 at drivers/regulator/core.c:2999 _regulator_disable
    ...
    
    Fix lis3lv02d_i2c_suspend() to not call poweroff() a second time if
    already runtime-suspended and add a poweron() call when necessary to
    make wakeup work.
    
    lis3lv02d_i2c_resume() has similar issues, with an added weirness that
    it always powers on the device if it is runtime suspended, after which
    the first runtime-resume will call poweron() again, causing the enabled
    count for the regulator to increase by 1 every suspend/resume. These
    unbalanced regulator_enable() calls cause the regulator to never
    be turned off and trigger the following WARN() on driver unbind:
    
    WARNING: CPU: 1 PID: 1724 at drivers/regulator/core.c:2396 _regulator_put
    
    Fix this by making lis3lv02d_i2c_resume() mirror the new suspend().
    
    Fixes: b1b9f7a4 ("misc: lis3lv02d_i2c: Add missing setting of the reg_ctrl callback")
    Reported-by: default avatarPaul Menzel <pmenzel@molgen.mpg.de>
    Closes: https://lore.kernel.org/regressions/5fc6da74-af0a-4aac-b4d5-a000b39a63a5@molgen.mpg.de/
    Cc: stable@vger.kernel.org
    Cc: regressions@lists.linux.dev
    Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
    Tested-by: Paul Menzel <pmenzel@molgen.mpg.de> # Dell XPS 15 7590
    Reviewed-by: default avatarPaul Menzel <pmenzel@molgen.mpg.de>
    Link: https://lore.kernel.org/r/20240220190035.53402-1-hdegoede@redhat.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    ac3e0384
lis3lv02d_i2c.c 6.92 KB