Hi Maciej, On Fri, Mar 2, 2018 at 5:42 AM, Maciej Purski <m.purski@xxxxxxxxxxx> wrote: > Hi all, > > this patchset adds a new mechanism to the framework - regulators' coupling. > > On Odroid XU3/4 and other Exynos5422 based boards there is a case, that > different devices on the board are supplied by different regulators > with non-fixed voltages. If one of these devices temporarily requires > higher voltage, there might occur a situation that the spread between > devices' voltages is so high, that there is a risk of changing > 'high' and 'low' states on the interconnection between devices powered > by those regulators. > > Algorithmicaly the problem was solved by: > Inderpal Singh <inderpal.s@xxxxxxxxxxx> > Doug Anderson <dianders@xxxxxxxxxxxx> > > The discussion on that subject can be found here: > https://lkml.org/lkml/2014/4/29/28 > > Therefore this patchset is an attempt to apply the idea to regulators core > as concluded in the discussion by Mark Brown and Doug Anderson. > > This feature is required to enable support for generic CPUfreq > and devfreq drivers for the mentioned boards. > > Note on the locking model: > When balancing voltage of a group of coupled regulators, we lock all > of them for the whole operation. When voltage of an individual regulator > is about to change, its suppliers are additionally locked. > > The current assumption is that an uncoupled regulator is a special case > of a coupled one, so they should share a common voltage setting path. This series breaks has reached linux-next 20180305 and it breaks booting on imx6: [ 0.269646] imx-pgc-pd imx-pgc-power-domain.0: Linked as a consumer to 20dc000.gpc [ 0.270348] [ 0.270363] ============================================ [ 0.270373] WARNING: possible recursive locking detected [ 0.270385] 4.16.0-rc3-next-20180305 #156 Not tainted [ 0.270397] -------------------------------------------- [ 0.270408] swapper/0/1 is trying to acquire lock: [ 0.270419] (&rdev->mutex){+.+.}, at: [<c04d80c4>] regulator_lock_supply+0x24/0x44 [ 0.270460] [ 0.270460] but task is already holding lock: [ 0.270471] (&rdev->mutex){+.+.}, at: [<c04dc6e4>] regulator_enable+0x78/0x298 [ 0.270502] [ 0.270502] other info that might help us debug this: [ 0.270513] Possible unsafe locking scenario: [ 0.270513] [ 0.270523] CPU0 [ 0.270532] ---- [ 0.270540] lock(&rdev->mutex); [ 0.270555] lock(&rdev->mutex); [ 0.270572] [ 0.270572] *** DEADLOCK *** [ 0.270572] [ 0.270585] May be due to missing lock nesting notation [ 0.270585] [ 0.270598] 3 locks held by swapper/0/1: [ 0.270606] #0: (&dev->mutex){....}, at: [<c057f368>] __driver_attach+0x58/0xcc [ 0.270642] #1: (&dev->mutex){....}, at: [<c057f378>] __driver_attach+0x68/0xcc [ 0.270672] #2: (&rdev->mutex){+.+.}, at: [<c04dc6e4>] regulator_enable+0x78/0x298 [ 0.270701] [ 0.270701] stack backtrace: [ 0.270719] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc3-next-20180305 #156 [ 0.270731] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) [ 0.270741] Backtrace: [ 0.270767] [<c010d154>] (dump_backtrace) from [<c010d414>] (show_stack+0x18/0x1c) [ 0.270783] r7:00000000 r6:60000093 r5:00000000 r4:c1078360 [ 0.270805] [<c010d3fc>] (show_stack) from [<c0a4724c>] (dump_stack+0xb4/0xe8) [ 0.270830] [<c0a47198>] (dump_stack) from [<c0174f4c>] (__lock_acquire+0x13a4/0x199c) [ 0.270848] r9:c17d75fc r8:c11ae35c r7:c17c73b0 r6:ec060000 r5:ec060570 r4:c11ae35c [ 0.270867] [<c0173ba8>] (__lock_acquire) from [<c0175d68>] (lock_acquire+0x70/0x90) [ 0.270883] r10:00000000 r9:ec195800 r8:00000001 r7:00000001 r6:60000013 r5:00000000 [ 0.270893] r4:ffffe000 [ 0.270914] [<c0175cf8>] (lock_acquire) from [<c0a60760>] (__mutex_lock+0x64/0x978) [ 0.270929] r8:00000001 r7:00000001 r6:00000000 r5:00000000 r4:ec00b89c [ 0.270947] [<c0a606fc>] (__mutex_lock) from [<c0a61098>] (mutex_lock_nested+0x24/0x2c) [ 0.270963] r10:00000000 r9:ec195800 r8:00000001 r7:00000001 r6:ec195800 r5:00000000 [ 0.270975] r4:ec00b800 [ 0.270992] [<c0a61074>] (mutex_lock_nested) from [<c04d80c4>] (regulator_lock_supply+0x24/0x44) [ 0.271013] [<c04d80a0>] (regulator_lock_supply) from [<c04da9b0>] (regulator_balance_voltage+0x298/0x584) [ 0.271024] r5:000b1008 r4:ec195800 [ 0.271042] [<c04da718>] (regulator_balance_voltage) from [<c04dc748>] (regulator_enable+0xdc/0x298) [ 0.271059] r10:00000000 r9:00000000 r8:00000001 r7:00000001 r6:ec195800 r5:ec195824 [ 0.271069] r4:00000001 [ 0.271086] [<c04dc66c>] (regulator_enable) from [<c04d6dd8>] (imx6_pm_domain_power_on+0x30/0x1b4) [ 0.271102] r9:00000000 r8:c102d114 r7:c1008908 r6:c102d114 r5:ec3d7a00 r4:ec3d7a00 [ 0.271119] [<c04d6da8>] (imx6_pm_domain_power_on) from [<c04d6d18>] (imx_pgc_power_domain_probe+0x64/0xf4) [ 0.271135] r8:c102d114 r7:ec49c810 r6:c102d114 r5:ec49c800 r4:ec3d7a00 [ 0.271153] [<c04d6cb4>] (imx_pgc_power_domain_probe) from [<c0580ef0>] (platform_drv_probe+0x54/0xb8) [ 0.271168] r7:fffffdfb r6:c102d114 r5:ec49c810 r4:ec49c810 [ 0.271189] [<c0580e9c>] (platform_drv_probe) from [<c057f288>] (driver_probe_device+0x2b0/0x338) [ 0.271204] r7:c17e234c r6:00000000 r5:c17e2348 r4:ec49c810 [ 0.271222] [<c057efd8>] (driver_probe_device) from [<c057f3d8>] (__driver_attach+0xc8/0xcc) [ 0.271237] r10:c0f00630 r9:00000000 r8:c1008908 r7:c1008908 r6:ec49c844 r5:c102d114 [ 0.271248] r4:ec49c810 r3:00000000 [ 0.271267] [<c057f310>] (__driver_attach) from [<c057d348>] (bus_for_each_dev+0x6c/0xbc) [ 0.271280] r7:c1008908 r6:c057f310 r5:c102d114 r4:00000000 [ 0.271298] [<c057d2dc>] (bus_for_each_dev) from [<c057eb64>] (driver_attach+0x20/0x28) [ 0.271314] r7:00000000 r6:c103b0a8 r5:ec479b00 r4:c102d114 [ 0.271332] [<c057eb44>] (driver_attach) from [<c057e588>] (bus_add_driver+0x18c/0x214) [ 0.271351] [<c057e3fc>] (bus_add_driver) from [<c057fdbc>] (driver_register+0x80/0x100) [ 0.271366] r7:c0e125e4 r6:c0f63850 r5:c0f41c18 r4:c102d114 [ 0.271383] [<c057fd3c>] (driver_register) from [<c0580e44>] (__platform_driver_register+0x38/0x4c) [ 0.271396] r5:c0f41c18 r4:ffffe000 [ 0.271418] [<c0580e0c>] (__platform_driver_register) from [<c0f41c30>] (imx_pgc_power_domain_driver_init+0x18/0x20) [ 0.271438] [<c0f41c18>] (imx_pgc_power_domain_driver_init) from [<c0102764>] (do_one_initcall+0x50/0x1a0) [ 0.271464] [<c0102714>] (do_one_initcall) from [<c0f00f04>] (kernel_init_freeable+0x118/0x1d0) [ 0.271481] r9:c0f63858 r8:000000f2 r7:c0e125e4 r6:c0f63850 r5:c1079f80 r4:c0f77ab4 [ 0.271508] [<c0f00dec>] (kernel_init_freeable) from [<c0a5c6f0>] (kernel_init+0x10/0x118) [ 0.271524] r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c0a5c6e0 [ 0.271533] r4:00000000 [ 0.271552] [<c0a5c6e0>] (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20) [ 0.271564] Exception stack(0xec069fb0 to 0xec069ff8) [ 0.271579] 9fa0: 00000000 00000000 00000000 00000000 [ 0.271594] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 0.271609] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 0.271621] r5:c0a5c6e0 r4:00000000 [ 0.271723] imx-pgc-pd imx-pgc-power-domain.1: Linked as a consumer to 20dc000.gpc [ 0.273566] 2020000.serial: ttymxc0 at MMIO 0x2020000 (irq = 26, base_baud = 5000000) is a IMX [ 1.660948] console [ttymxc0] enabled [ 1.666242] 21ec000.serial: ttymxc2 at MMIO 0x21ec000 (irq = 65, base_baud = 5000000) is a IMX [ 1.683484] etnaviv etnaviv: bound 130000.gpu (ops gpu_ops) [ 1.689464] etnaviv etnaviv: bound 134000.gpu (ops gpu_ops) If I revert this series I am able to boot 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