• Fabio Estevam's avatar
    video: imxfb: Do not crash on reboot · e6b267ce
    Fabio Estevam authored
    Issuing a "reboot" command after the LCD times out causes the following
    warnings:
    
    Requesting system reboot
    ------------[ cut here ]------------
    WARNING: at drivers/clk/clk.c:471 clk_disable+0x24/0x50()
    Modules linked in:
    [<c001ad90>] (unwind_backtrace+0x0/0xf4) from [<c0025aac>] (warn_slowpath_common+0x48/0x60)
    [<c0025aac>] (warn_slowpath_common+0x48/0x60) from [<c0025ae0>] (warn_slowpath_null+0x1c/0x24)
    [<c0025ae0>] (warn_slowpath_null+0x1c/0x24) from [<c03960a0>] (clk_disable+0x24/0x50)
    [<c03960a0>] (clk_disable+0x24/0x50) from [<c02695a0>] (imxfb_disable_controller+0x48/0x7c)
    [<c02695a0>] (imxfb_disable_controller+0x48/0x7c) from [<c029d838>] (platform_drv_shutdown+0x18/0x1c)
    [<c029d838>] (platform_drv_shutdown+0x18/0x1c) from [<c02990fc>] (device_shutdown+0x48/0x14c)
    [<c02990fc>] (device_shutdown+0x48/0x14c) from [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c)
    [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) from [<c003d0e4>] (kernel_restart+0xc/0x48)
    [<c003d0e4>] (kernel_restart+0xc/0x48) from [<c003d1e8>] (sys_reboot+0xc0/0x1bc)
    [<c003d1e8>] (sys_reboot+0xc0/0x1bc) from [<c0014ca0>] (ret_fast_syscall+0x0/0x2c)
    ---[ end trace da6b502ca79c854f ]---
    ------------[ cut here ]------------
    WARNING: at drivers/clk/clk.c:380 clk_unprepare+0x1c/0x2c()
    Modules linked in:
    [<c001ad90>] (unwind_backtrace+0x0/0xf4) from [<c0025aac>] (warn_slowpath_common+0x48/0x60)
    [<c0025aac>] (warn_slowpath_common+0x48/0x60) from [<c0025ae0>] (warn_slowpath_null+0x1c/0x24)
    [<c0025ae0>] (warn_slowpath_null+0x1c/0x24) from [<c0396338>] (clk_unprepare+0x1c/0x2c)
    [<c0396338>] (clk_unprepare+0x1c/0x2c) from [<c02695a8>] (imxfb_disable_controller+0x50/0x7c)
    [<c02695a8>] (imxfb_disable_controller+0x50/0x7c) from [<c029d838>] (platform_drv_shutdown+0x18/0x1c)
    [<c029d838>] (platform_drv_shutdown+0x18/0x1c) from [<c02990fc>] (device_shutdown+0x48/0x14c)
    [<c02990fc>] (device_shutdown+0x48/0x14c) from [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c)
    [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) from [<c003d0e4>] (kernel_restart+0xc/0x48)
    [<c003d0e4>] (kernel_restart+0xc/0x48) from [<c003d1e8>] (sys_reboot+0xc0/0x1bc)
    [<c003d1e8>] (sys_reboot+0xc0/0x1bc) from [<c0014ca0>] (ret_fast_syscall+0x0/0x2c)
    ---[ end trace da6b502ca79c8550 ]---
    ------------[ cut here ]------------
    
    This happens because "reboot" triggers imxfb_shutdown(), which calls
    imxfb_disable_controller with the clocks already disabled.
    
    To prevent this, add a clock enabled status so that we can check if the clocks
    are enabled before disabling them.
    Acked-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
    Signed-off-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
    Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
    e6b267ce
imxfb.c 23.7 KB