Hi Morimoto-san,
While booting Ebisu-4D, I saw the below warnings (once).
rcar_sound ec500000.sound: can't use clk 1
rsnd_adg_clk_control() failed to enable CLKB, but continues.
------------[ cut here ]------------ clk-multiplier already disabled WARNING: CPU: 1 PID: 52 at drivers/clk/clk.c:952 clk_core_disable+0x30/0x9c Modules linked in: CPU: 1 PID: 52 Comm: kworker/1:2 Not tainted 5.10.0-rc7-rcar3-initrd-00582-gadecf297acf4-dirty #183 Hardware name: Renesas Ebisu-4D board based on r8a77990 (DT) Workqueue: events deferred_probe_work_func pstate: 60000085 (nZCv daIf -PAN -UAO -TCO BTYPE=--) pc : clk_core_disable+0x30/0x9c lr : clk_core_disable+0x30/0x9c sp : ffffffc010f939f0 x29: ffffffc010f939f0 x28: 0000000000000000 x27: ffffff800949eb00 x26: ffffff80093c40f8 x25: 0000000000000001 x24: ffffffc010805fea x23: 0000000000000000 x22: ffffff80082b8810 x21: ffffff80093c4080 x20: ffffff8009368b00 x19: ffffff8009368b00 x18: 0000000000000000 x17: 000000004ef774c4 x16: 0000000000000014 x15: ffffffffffffffff x14: ffffffc010b8e8b0 x13: fffffffffff9fd47 x12: 0720072007200720 x11: fffffffffffc0000 x10: ffffffc010b8e8d8 x9 : 0720072007200720 x8 : 2079646165726c61 x7 : 0000000000000004 x6 : 00000000ffffe6ad x5 : ffffffc010f93718 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 00000000ffffffff x1 : 0000000000000000 x0 : 0000000000000000 Call trace: clk_core_disable+0x30/0x9c clk_core_disable_lock+0x24/0x3c clk_disable+0x20/0x30 rsnd_adg_clk_control+0xa0/0xd4 rsnd_adg_remove+0x58/0x6c rsnd_probe+0x134/0x3cc
Something else fails (-EPROBE_DEFER?), and thus rsnd_adg_remove() is called. The latter disables all clocks, including the one that failed to enable before, leading to the warning.
platform_drv_probe+0x54/0xa4 really_probe+0x234/0x340 driver_probe_device+0xa0/0xb0 __device_attach_driver+0x9c/0xa8 bus_for_each_drv+0x9c/0xc4 __device_attach+0xd4/0x140 device_initial_probe+0x14/0x20 bus_probe_device+0x30/0x94 deferred_probe_work_func+0x9c/0xb0 process_one_work+0x180/0x1f0 process_scheduled_works+0x44/0x48 worker_thread+0x1ec/0x270 kthread+0xdc/0xec ret_from_fork+0x10/0x30 ---[ end trace 8d8c2a1b7537ca36 ]--- ------------[ cut here ]------------ clk-multiplier already unprepared WARNING: CPU: 1 PID: 52 at drivers/clk/clk.c:810 clk_core_unprepare+0x30/0xd0 [...] ---[ end trace 8d8c2a1b7537ca37 ]---
Gr{oetje,eeting}s,
Geert