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Subject: Re: [PATCH v7 16/21] memory: mtk-smi: Add bus_sel for mt8183
To:     Pi-Hsun Shih <pihsun@chromium.org>, Yong Wu <yong.wu@mediatek.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Evan Green <evgreen@chromium.org>,
        Tomasz Figa <tfiga@google.com>,
        Will Deacon <will.deacon@arm.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>, srv_heupstream@mediatek.com,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@lists.infradead.org>,
        iommu@lists.linux-foundation.org, yingjoe.chen@mediatek.com,
        youlin.pei@mediatek.com, Nicolas Boichat <drinkcat@chromium.org>,
        anan.sun@mediatek.com, Matthias Kaehlcke <mka@chromium.org>
References: <1560169080-27134-1-git-send-email-yong.wu@mediatek.com>
 <1560169080-27134-17-git-send-email-yong.wu@mediatek.com>
 <CANdKZ0emRPcTcL7Yq5nLH5z2_9fBuuczKehA8oEi0b+je15RPg@mail.gmail.com>
From:   Matthias Brugger <matthias.bgg@gmail.com>
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Date:   Mon, 17 Jun 2019 18:28:21 +0200
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On 13/06/2019 10:20, Pi-Hsun Shih wrote:
> (Sorry for the possibly double-posting, my last mail got rejected by
> some mailing lists.)
> 
> Hi,
> When I tested this patch series (Based on linux 5.2.0-rc2, and with
> various other patch series about MT8183) with lockdep enabled, and I'm
> seeing the following lockdep warning on boot.
> 
> By bisecting the commits, the first commit that introduce this warning
> is this patch. The warning also doesn't appear if

Are you sure about this?
From the lockdep call graph it looks more like patch
[PATCH v7 15/21] memory: mtk-smi: Invoke pm runtime_callback to enable clocks
has something to do with it.

But not an expert either, sorry.

Regards,
Matthias

> https://lore.kernel.org/patchwork/patch/1086582/ and
> https://lore.kernel.org/patchwork/patch/1086583/ are not applied.
> 
> Do anyone have idea on why this is happening, or any suggestion on
> which part I should be digging into to figure this out? Thanks.
> 
> [    4.664194] ======================================================
> [    4.670368] WARNING: possible circular locking dependency detected
> [    4.676545] 5.2.0-rc2-next-20190528-44527-g6c94b6475c04 #20 Tainted: G S
> [    4.684539] ------------------------------------------------------
> [    4.690714] kworker/4:1/51 is trying to acquire lock:
> [    4.695760] (____ptrval____) (regulator_list_mutex){+.+.},
> at:regulator_lock_dependent+0xdc/0x6c4
> [    4.704732]
> [    4.704732] but task is already holding lock:
> [    4.710556] (____ptrval____) (&genpd->mlock/1){+.+.},
> at:genpd_lock_nested_mtx+0x24/0x30
> [    4.718740]
> [    4.718740] which lock already depends on the new lock.
> [    4.718740]
> [    4.726908]
> [    4.726908] the existing dependency chain (in reverse order) is:
> [    4.734382]
> [    4.734382] -> #4 (&genpd->mlock/1){+.+.}:
> [    4.739963]        __mutex_lock_common+0x1a0/0x1fe8
> [    4.744836]        mutex_lock_nested+0x40/0x50
> [    4.749275]        genpd_lock_nested_mtx+0x24/0x30
> [    4.754063]        genpd_add_subdomain+0x150/0x524
> [    4.758850]        pm_genpd_add_subdomain+0x3c/0x5c
> [    4.763723]        scpsys_probe+0x520/0xe78
> [    4.767902]        platform_drv_probe+0xf4/0x134
> [    4.772517]        really_probe+0x214/0x4dc
> [    4.776696]        driver_probe_device+0xcc/0x1d4
> [    4.781396]        __device_attach_driver+0x10c/0x180
> [    4.786442]        bus_for_each_drv+0x124/0x184
> [    4.790968]        __device_attach+0x1c0/0x2d8
> [    4.795407]        device_initial_probe+0x20/0x2c
> [    4.800106]        bus_probe_device+0x80/0x16c
> [    4.804546]        deferred_probe_work_func+0x120/0x168
> [    4.809767]        process_one_work+0x858/0x1208
> [    4.814379]        worker_thread+0x9ec/0xcb8
> [    4.818644]        kthread+0x2b8/0x2d0
> [    4.822391]        ret_from_fork+0x10/0x18
> [    4.826480]
> [    4.826480] -> #3 (&genpd->mlock){+.+.}:
> [    4.831880]        __mutex_lock_common+0x1a0/0x1fe8
> [    4.836752]        mutex_lock_nested+0x40/0x50
> [    4.841190]        genpd_lock_mtx+0x20/0x2c
> [    4.845369]        genpd_runtime_resume+0x140/0x434
> [    4.850241]        __rpm_callback+0xb0/0x1e4
> [    4.854506]        rpm_callback+0x54/0x1a8
> [    4.858597]        rpm_resume+0xc6c/0x10c4
> [    4.862689]        __pm_runtime_resume+0xb4/0x124
> [    4.867387]        device_link_add+0x598/0x8d0
> [    4.871829]        mtk_smi_larb_probe+0x2b0/0x340
> [    4.876528]        platform_drv_probe+0xf4/0x134
> [    4.881141]        really_probe+0x214/0x4dc
> [    4.885320]        driver_probe_device+0xcc/0x1d4
> [    4.890020]        __device_attach_driver+0x10c/0x180
> [    4.895066]        bus_for_each_drv+0x124/0x184
> [    4.899591]        __device_attach+0x1c0/0x2d8
> [    4.904031]        device_initial_probe+0x20/0x2c
> [    4.908730]        bus_probe_device+0x80/0x16c
> [    4.913169]        deferred_probe_work_func+0x120/0x168
> [    4.918387]        process_one_work+0x858/0x1208
> [    4.923000]        worker_thread+0x9ec/0xcb8
> [    4.927264]        kthread+0x2b8/0x2d0
> [    4.931009]        ret_from_fork+0x10/0x18
> [    4.935098]
> [    4.935098] -> #2 (dpm_list_mtx){+.+.}:
> [    4.940412]        __mutex_lock_common+0x1a0/0x1fe8
> [    4.945284]        mutex_lock_nested+0x40/0x50
> [    4.949722]        device_pm_lock+0x1c/0x24
> [    4.953900]        device_link_add+0x98/0x8d0
> [    4.958252]        _regulator_get+0x3f0/0x504
> [    4.962606]        _devm_regulator_get+0x58/0xb8
> [    4.967218]        devm_regulator_get+0x28/0x34
> [    4.971746]        pwm_backlight_probe+0x61c/0x1b90
> [    4.976617]        platform_drv_probe+0xf4/0x134
> [    4.981230]        really_probe+0x214/0x4dc
> [    4.985409]        driver_probe_device+0xcc/0x1d4
> [    4.990108]        device_driver_attach+0xe4/0x104
> [    4.994894]        __driver_attach+0x134/0x14c
> [    4.999333]        bus_for_each_dev+0x120/0x180
> [    5.003859]        driver_attach+0x48/0x54
> [    5.007950]        bus_add_driver+0x2ac/0x44c
> [    5.012303]        driver_register+0x160/0x288
> [    5.016742]        __platform_driver_register+0xcc/0xdc
> [    5.021964]        pwm_backlight_driver_init+0x1c/0x24
> [    5.027097]        do_one_initcall+0x38c/0x994
> [    5.031536]        do_initcall_level+0x3a4/0x4b8
> [    5.036148]        do_basic_setup+0x84/0xa0
> [    5.036153]        kernel_init_freeable+0x23c/0x324
> [    5.036158]        kernel_init+0x14/0x110
> [    5.036164]        ret_from_fork+0x10/0x18
> [    5.036166]
> [    5.036166] -> #1 (device_links_lock){+.+.}:
> [    5.065905]        __mutex_lock_common+0x1a0/0x1fe8
> [    5.070777]        mutex_lock_nested+0x40/0x50
> [    5.075215]        device_link_remove+0x40/0xe0
> [    5.079740]        _regulator_put+0x104/0x2d8
> [    5.084093]        regulator_put+0x30/0x44
> [    5.088184]        devm_regulator_release+0x38/0x44
> [    5.093056]        release_nodes+0x604/0x670
> [    5.097320]        devres_release_all+0x70/0x8c
> [    5.101846]        really_probe+0x270/0x4dc
> [    5.106024]        driver_probe_device+0xcc/0x1d4
> [    5.110724]        device_driver_attach+0xe4/0x104
> [    5.115510]        __driver_attach+0x134/0x14c
> [    5.119949]        bus_for_each_dev+0x120/0x180
> [    5.124474]        driver_attach+0x48/0x54
> [    5.128566]        bus_add_driver+0x2ac/0x44c
> [    5.132919]        driver_register+0x160/0x288
> [    5.137357]        __platform_driver_register+0xcc/0xdc
> [    5.142576]        pwm_backlight_driver_init+0x1c/0x24
> [    5.147708]        do_one_initcall+0x38c/0x994
> [    5.152146]        do_initcall_level+0x3a4/0x4b8
> [    5.156758]        do_basic_setup+0x84/0xa0
> [    5.160936]        kernel_init_freeable+0x23c/0x324
> [    5.165807]        kernel_init+0x14/0x110
> [    5.169813]        ret_from_fork+0x10/0x18
> [    5.173901]
> [    5.173901] -> #0 (regulator_list_mutex){+.+.}:
> [    5.179910]        lock_acquire+0x350/0x4d4
> [    5.184088]        __mutex_lock_common+0x1a0/0x1fe8
> [    5.184095]        mutex_lock_nested+0x40/0x50
> [    5.197475]        regulator_lock_dependent+0xdc/0x6c4
> [    5.197482]        regulator_disable+0xa0/0x138
> [    5.197487]        scpsys_power_off+0x38c/0x4bc
> [    5.197495]        genpd_power_off+0x3d8/0x6a0
> [    5.209399]        genpd_power_off+0x530/0x6a0
> [    5.209406]        genpd_power_off_work_fn+0x74/0xc0
> [    5.209411]        process_one_work+0x858/0x1208
> [    5.209419]        worker_thread+0x9ec/0xcb8
> [    5.219067]        kthread+0x2b8/0x2d0
> [    5.219073]        ret_from_fork+0x10/0x18
> [    5.219077]
> [    5.219077] other info that might help us debug this:
> [    5.219077]
> [    5.219080] Chain exists of:
> [    5.219080]   regulator_list_mutex --> &genpd->mlock --> &genpd->mlock/1
> [    5.219080]
> [    5.228039]  Possible unsafe locking scenario:
> [    5.228039]
> [    5.228042]        CPU0                    CPU1
> [    5.228046]        ----                    ----
> [    5.228048]   lock(&genpd->mlock/1);
> [    5.228058]                                lock(&genpd->mlock);
> [    5.311647]                                lock(&genpd->mlock/1);
> [    5.317736]   lock(regulator_list_mutex);
> [    5.321742]
> [    5.321742]  *** DEADLOCK ***
> [    5.321742]
> [    5.327655] 4 locks held by kworker/4:1/51:
> [    5.331831]  #0: (____ptrval____) ((wq_completion)pm){+.+.},
> at:process_one_work+0x57c/0x1208
> [    5.340444]  #1: (____ptrval____)
> ((work_completion)(&genpd->power_off_work)){+.+.},
> at:process_one_work+0x5b8/0x1208
> [    5.351139]  #2: (____ptrval____) (&genpd->mlock){+.+.},
> at:genpd_lock_mtx+0x20/0x2c
> [    5.358970]  #3: (____ptrval____) (&genpd->mlock/1){+.+.},
> at:genpd_lock_nested_mtx+0x24/0x30
> [    5.367584]
> [    5.367584] stack backtrace:
> [    5.371939] CPU: 4 PID: 51 Comm: kworker/4:1 Tainted: G S
>      5.2.0-rc2-next-20190528-44527-g6c94b6475c04 #20
> [    5.382809] Workqueue: pm genpd_power_off_work_fn
> [    5.382816] Call trace:
> [    5.382822]  dump_backtrace+0x0/0x2c0
> [    5.382830]  show_stack+0x20/0x2c
> [    5.409174]  dump_stack+0x10c/0x17c
> [    5.412659]  print_circular_bug+0x42c/0x4d0
> [    5.416838]  __lock_acquire+0x4c88/0x5484
> [    5.420843]  lock_acquire+0x350/0x4d4
> [    5.424500]  __mutex_lock_common+0x1a0/0x1fe8
> [    5.428851]  mutex_lock_nested+0x40/0x50
> [    5.432770]  regulator_lock_dependent+0xdc/0x6c4
> [    5.437383]  regulator_disable+0xa0/0x138
> [    5.441389]  scpsys_power_off+0x38c/0x4bc
> [    5.445393]  genpd_power_off+0x3d8/0x6a0
> [    5.449310]  genpd_power_off+0x530/0x6a0
> [    5.453229]  genpd_power_off_work_fn+0x74/0xc0
> [    5.457667]  process_one_work+0x858/0x1208
> [    5.461758]  worker_thread+0x9ec/0xcb8
> [    5.465503]  kthread+0x2b8/0x2d0
> [    5.468727]  ret_from_fork+0x10/0x18
> 
> On Mon, Jun 10, 2019 at 8:21 PM Yong Wu <yong.wu@mediatek.com> wrote:
>> ...
>> +       } else {
>> +               res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +               common->base = devm_ioremap_resource(dev, res);
>> +               if (IS_ERR(common->base))
>> +                       return PTR_ERR(common->base);
>>         }
>>         pm_runtime_enable(dev);
>>         platform_set_drvdata(pdev, common);