S5P-TV: Warning for regulator unbalanced disables

Hi,

After implementing genpd framework for EXYNOS4, (Ref commit 91cfbd4 "ARM: EXYNOS: Hook up power domains to generic power domain infrastructure" in Kukjin's for-next branch), we are getting following warning from s5p-hdmi driver.

The test was done on Origen board with code based on 3.3-rc4 and Kukjin's for-next branch. [1]

------------[ cut here ]------------
WARNING: at drivers/regulator/core.c:1503 _regulator_disable+0xf8/0x164()
unbalanced disables for VMIPI_1.1V
Modules linked in:

regulator_init_complete: VDD_G3D_1.1V: incomplete constraints, leaving on [<c0014624>] (unwind_backtrace+0x0/0xf8) from [<c00232fc>] (warn_slowpath_common+0x54/0x64)
[<c00232fc>] (warn_slowpath_common+0x54/0x64) from [<c00233a0>] (warn_slowpath_fmt+0x30/0x40)
[<c00233a0>] (warn_slowpath_fmt+0x30/0x40) from [<c01ab9b8>] (_regulator_disable+0xf8/0x164)
[<c01ab9b8>] (_regulator_disable+0xf8/0x164) from [<c01aba40>] (regulator_disable+0x1c/0x48)
[<c01aba40>] (regulator_disable+0x1c/0x48) from [<c01abcf4>] (regulator_bulk_disable+0x24/0x8c)
regulator_init_complete: VADC_3.3V: incomplete constraints, leaving on [<c01abcf4>] (regulator_bulk_disable+0x24/0x8c) from [<c028d874>] (hdmi_runtime_suspend+0x28/0x30)
[<c028d874>] (hdmi_runtime_suspend+0x28/0x30) from [<c01edac4>] (pm_genpd_default_save_state+0x48/0x5c)
[<c01edac4>] (pm_genpd_default_save_state+0x48/0x5c) from [<c01eeed4>] (pm_genpd_poweroff+0x224/0x3f0)
[<c01eeed4>] (pm_genpd_poweroff+0x224/0x3f0) from [<c01ef190>] (genpd_power_off_work_fn+0x1c/0x28)
[<c01ef190>] (genpd_power_off_work_fn+0x1c/0x28) from [<c0036ac0>] (process_one_work+0x118/0x3b0)
regulator_init_complete: VMIPI_1.8V: incomplete constraints, leaving on [<c0036ac0>] (process_one_work+0x118/0x3b0) from [<c0039424>] (worker_thread+0x18c/0x3a0)
[<c0039424>] (worker_thread+0x18c/0x3a0) from [<c003d734>] (kthread+0x8c/0x90)
[<c003d734>] (kthread+0x8c/0x90) from [<c000f278>] (kernel_thread_exit+0x0/0x8)

---[ end trace 9e20783f432f4c81 ]---

[1] git://git.linaro.org/people/tushar/linux-linaro-samsung.git
(test/hdmi-pd)

Tushar Behera

Hi Tushar,

(snipped)

Thanks for the report. We know about this issue. It is not really related to regulators nor s5p-tv driver. There is something broken (or misused) in the gen_pd driver and its implementation for Exysno4 hw. If you dig a bit into the problem You can observe the following call sequence on device probe:

exynos4_genpd_enable()
s5p_tv_runtime_disable()
exynos4_genpd_disable()

So the call to s5p_tv_runtime_disable is not balanced with s5p_tv_runtime_resume() what causes the error you have posted. It looks that runtime pw framework makes some wrong assumptions about the state of the device once power domain has been registered.

The same problem appears for s5p-fimc and s5p-mfc, although it is not observed as kernel error, but these devices also suffers from it - their clocks get disabled one time too much so they do not operate correctly.

We are investigating this issue further.

Best regards
--
Marek Szyprowski
Samsung Poland R&D Center

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