Re: [PATCH 0/7] PM / devfreq: Add NoCP devfreq-event and support busfreq on exyno5422-odroidxu3

From: Anand Moon
Date: Fri Apr 08 2016 - 14:11:45 EST

Hi Chanwoo,

On 8 April 2016 at 10:30, Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote:
> This patchset support the AMBA bus frequency scaling on Exynos5422-based
> Odroid-XU3 board. But, this series only support the bus frequency scaling
> for INT (Internal) block using VDD_INT power line.
>
> Also, to support the bus frequency scaling for Exynos542x SoC,
> Exynos542x SoC has the specific 'NoC (Network on Chip) Probe' device
> to measure the transfered data traffic on NoC (Network on Chip)
> instead of PPMU (Platform Performance Monitoring Unit). NoC Probe device
> provide the utilization for INT block of Exynos542x SoC.
>
> The generic exynos-bus frequency driver uses the 'NoC Probe' devfreq-event
> device (drivers/devfreq/event/exynos-nocp.c) without any modification.
> Just add the phandle of 'NoC Probe' dt node to bus dt node.
>
> Depend on:
> This patchset depends on patch[1] which support the generic exynos-bus
> frequency driver.
>
> [1] https://lkml.org/lkml/2016/4/8/14
> - [PATCH v8 00/20] PM / devferq: Add generic exynos bus frequency driver and new passive governor
>
> Chanwoo Choi (7):
> PM / devfreq: event: Add new Exynos NoC probe driver
> PM / devfreq: exynos: Add the detailed correlation for Exynos5422 bus
> ARM: dts: Add NoC Probe dt node for Exynos542x SoC
> dt-bindings: clock: Add the clock id for ACLK clock of Exynos542x SoC
> clk: samsung: exynos542x: Add the clock id for ACLK
> ARM: dts: Add bus nodes using VDD_INT for Exynos542x SoC
> ARM: dts: Add support of Bus frequency using VDD_INT for exynos5422-odroidxu3
>
> .../bindings/devfreq/event/exynos-nocp.txt | 86 +++++
> .../devicetree/bindings/devfreq/exynos-bus.txt | 19 +
> arch/arm/boot/dts/exynos5420.dtsi | 407 +++++++++++++++++++++
> arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 99 +++++
> drivers/clk/samsung/clk-exynos5420.c | 85 +++--
> drivers/devfreq/event/Kconfig | 8 +
> drivers/devfreq/event/Makefile | 2 +
> drivers/devfreq/event/exynos-nocp.c | 247 +++++++++++++
> drivers/devfreq/event/exynos-nocp.h | 78 ++++
> include/dt-bindings/clock/exynos5420.h | 24 +-
> 10 files changed, 1024 insertions(+), 31 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/devfreq/event/exynos-nocp.txt
> create mode 100644 drivers/devfreq/event/exynos-nocp.c
> create mode 100644 drivers/devfreq/event/exynos-nocp.h
>
> --
> 1.9.1
>

I am observing following deadlock. Both on Odroid U3 and Odroid XU4.

[ 7.718372] [ INFO: possible recursive locking detected ]
[ 7.723747] 4.6.0-rc2-xu4ml #4 Not tainted
[ 7.727817] ---------------------------------------------
[ 7.733190] kworker/u16:1/136 is trying to acquire lock:
[ 7.738476] (&devfreq->lock){+.+.+.}, at: [<c05be41c>]
update_devfreq_passive+0x2c/0x88
[ 7.746534]
[ 7.746534] but task is already holding lock:
[ 7.752339] (&devfreq->lock){+.+.+.}, at: [<c05bd838>]
devfreq_monitor+0x1c/0x78
[ 7.759791]
[ 7.759791] other info that might help us debug this:
[ 7.766291] Possible unsafe locking scenario:
[ 7.766291]
[ 7.766307] usb 5-1: new high-speed USB device number 2 using xhci-hcd
[ 7.778682] CPU0
[ 7.781107] ----
[ 7.783533] lock(&devfreq->lock);
[ 7.786999] lock(&devfreq->lock);
[ 7.790467]
[ 7.790467] *** DEADLOCK ***
[ 7.790467]
[ 7.796359] May be due to missing lock nesting notation
[ 7.796359]
[ 7.803120] 4 locks held by kworker/u16:1/136:
[ 7.807537] #0: ("%s"("devfreq_wq")){.+.+..}, at: [<c013b41c>]
process_one_work+0x13c/0x454
[ 7.816029] #1: ((&(&devfreq->work)->work)){+.+...}, at:
[<c013b41c>] process_one_work+0x13c/0x454
[ 7.825128] #2: (&devfreq->lock){+.+.+.}, at: [<c05bd838>]
devfreq_monitor+0x1c/0x78
[ 7.833013] #3: (&nh->srcu){......}, at: [<c014309c>]
__srcu_notifier_call_chain+0x54/0xe0
[ 7.841419]
[ 7.841419] stack backtrace:
[ 7.845758] CPU: 1 PID: 136 Comm: kworker/u16:1 Not tainted
4.6.0-rc2-xu4ml #4
[ 7.852946] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[ 7.859017] Workqueue: devfreq_wq devfreq_monitor
[ 7.863717] [<c010eb48>] (unwind_backtrace) from [<c010b884>]
(show_stack+0x10/0x14)
[ 7.871417] [<c010b884>] (show_stack) from [<c037715c>]
(dump_stack+0xa4/0xd0)
[ 7.878613] [<c037715c>] (dump_stack) from [<c017112c>]
(__lock_acquire+0x1ce8/0x207c)
[ 7.886492] [<c017112c>] (__lock_acquire) from [<c0172010>]
(lock_acquire+0x90/0xd4)
[ 7.892726] usb 5-1: New USB device found, idVendor=0bda, idProduct=8153
[ 7.892737] usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=6
[ 7.892745] usb 5-1: Product: USB 10/100/1000 LAN
[ 7.892753] usb 5-1: Manufacturer: Realtek
[ 7.892761] usb 5-1: SerialNumber: 000001000000
[ 7.921248] [<c0172010>] (lock_acquire) from [<c075d298>]
(mutex_lock_nested+0x78/0x4ec)
[ 7.929301] [<c075d298>] (mutex_lock_nested) from [<c05be41c>]
(update_devfreq_passive+0x2c/0x88)
[ 7.938138] [<c05be41c>] (update_devfreq_passive) from [<c05be4c0>]
(devfreq_passive_notifier_call+0x48/0x50)
[ 7.948016] [<c05be4c0>] (devfreq_passive_notifier_call) from
[<c0142d84>] (notifier_call_chain+0x54/0xa4)
[ 7.957633] [<c0142d84>] (notifier_call_chain) from [<c01430e0>]
(__srcu_notifier_call_chain+0x98/0xe0)
[ 7.966991] [<c01430e0>] (__srcu_notifier_call_chain) from
[<c0143140>] (srcu_notifier_call_chain+0x18/0x20)
[ 7.976783] [<c0143140>] (srcu_notifier_call_chain) from
[<c05bd774>] (update_devfreq+0xe4/0x18c)
[ 7.985622] [<c05bd774>] (update_devfreq) from [<c05bd840>]
(devfreq_monitor+0x24/0x78)
[ 7.993595] [<c05bd840>] (devfreq_monitor) from [<c013b48c>]
(process_one_work+0x1ac/0x454)
[ 8.001913] [<c013b48c>] (process_one_work) from [<c013b784>]
(worker_thread+0x50/0x508)
[ 8.009976] [<c013b784>] (worker_thread) from [<c0141cf4>]
(kthread+0xf8/0x110)
[ 8.017254] [<c0141cf4>] (kthread) from [<c0107750>]
(ret_from_fork+0x14/0x24)

Best Regards
-Anand Moon