WARNING in clk_core_disable and clk_core_unprepare with imx6q-cpufreq and schedutil governor

[Robert Hancock]

Hello, I have been trying out the schedutil governor using a 5.4.61 kernel on an iMX6D platform, but am occasionally seeing the warnings below in the kernel log. Is this a known issue? I didn't notice any relevant changes to imx6q-cpufreq between 5.4 and master.

------------[ cut here ]------------
WARNING: CPU: 1 PID: 166 at drivers/clk/clk.c:958 clk_core_disable+0xc4/0xcc
pll1_sys already disabled
Modules linked in: sed_fan_monitor(O) sed_axi_dma_sg(O) sed_pcie_axi(O)
CPU: 1 PID: 166 Comm: sugov:0 Tainted: G           O      5.4.61 #2
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[<c0110a74>] (unwind_backtrace) from [<c010b924>] (show_stack+0x10/0x14)
[<c010b924>] (show_stack) from [<c06e2d20>] (dump_stack+0x90/0xa4)
[<c06e2d20>] (dump_stack) from [<c01214ec>] (__warn+0xbc/0xd8)
[<c01214ec>] (__warn) from [<c01215a0>] (warn_slowpath_fmt+0x98/0xc4)
[<c01215a0>] (warn_slowpath_fmt) from [<c03ef9d0>] (clk_core_disable+0xc4/0xcc)
[<c03ef9d0>] (clk_core_disable) from [<c03efac8>] (clk_core_disable_lock+0x18/0x24)
[<c03efac8>] (clk_core_disable_lock) from [<c051e4c0>] (imx6q_set_target+0x4a8/0x500)
[<c051e4c0>] (imx6q_set_target) from [<c0518568>] (__cpufreq_driver_target+0x220/0x534)
[<c0518568>] (__cpufreq_driver_target) from [<c0164dd8>] (sugov_work+0x48/0x54)
[<c0164dd8>] (sugov_work) from [<c013f9e8>] (kthread_worker_fn+0xf8/0x1fc)
[<c013f9e8>] (kthread_worker_fn) from [<c0140680>] (kthread+0x150/0x190)
[<c0140680>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0xecb97fb0 to 0xecb97ff8)
7fa0:                                     00000000 00000000 00000000 00000000
7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
7fe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end trace 37734437c8c6ed11 ]---
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WARNING: CPU: 1 PID: 166 at drivers/clk/clk.c:816 clk_core_unprepare+0xec/0x148
pll1_sys already unprepared
Modules linked in: sed_fan_monitor(O) sed_axi_dma_sg(O) sed_pcie_axi(O)
CPU: 1 PID: 166 Comm: sugov:0 Tainted: G        W  O      5.4.61 #2
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[<c0110a74>] (unwind_backtrace) from [<c010b924>] (show_stack+0x10/0x14)
[<c010b924>] (show_stack) from [<c06e2d20>] (dump_stack+0x90/0xa4)
[<c06e2d20>] (dump_stack) from [<c01214ec>] (__warn+0xbc/0xd8)
[<c01214ec>] (__warn) from [<c01215a0>] (warn_slowpath_fmt+0x98/0xc4)
[<c01215a0>] (warn_slowpath_fmt) from [<c03f0ca4>] (clk_core_unprepare+0xec/0x148)
[<c03f0ca4>] (clk_core_unprepare) from [<c03f14f8>] (clk_unprepare+0x24/0x2c)
[<c03f14f8>] (clk_unprepare) from [<c051e4c8>] (imx6q_set_target+0x4b0/0x500)
[<c051e4c8>] (imx6q_set_target) from [<c0518568>] (__cpufreq_driver_target+0x220/0x534)
[<c0518568>] (__cpufreq_driver_target) from [<c0164dd8>] (sugov_work+0x48/0x54)
[<c0164dd8>] (sugov_work) from [<c013f9e8>] (kthread_worker_fn+0xf8/0x1fc)
[<c013f9e8>] (kthread_worker_fn) from [<c0140680>] (kthread+0x150/0x190)
[<c0140680>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0xecb97fb0 to 0xecb97ff8)
7fa0:                                     00000000 00000000 00000000 00000000
7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
7fe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end trace 37734437c8c6ed12 ]---


-- 

Robert Hancock 
Senior Hardware Designer 
Calian - SED