linux-kernel - Re: [PATCH v3 04/10] pmdomain: mediatek: Refactor bus protection regmaps retrieval

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Message-ID: <5db8017f-715d-4a30-b6b6-d3360ed53dec@collabora.com>
Date: Fri, 21 Nov 2025 13:57:28 +0100
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
To: Macpaul Lin (林智斌) <Macpaul.Lin@...iatek.com>,
 "linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
 Sjoerd Simons <sjoerd@...labora.com>
Cc: Pablo Sun (孫毓翔) <pablo.sun@...iatek.com>,
 "lihongbo22@...wei.com" <lihongbo22@...wei.com>,
 "robh@...nel.org" <robh@...nel.org>,
 "kernel@...labora.com" <kernel@...labora.com>,
 "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
 Moudy Ho (何宗原) <Moudy.Ho@...iatek.com>,
 "mbrugger@...e.com" <mbrugger@...e.com>,
 "conor+dt@...nel.org" <conor+dt@...nel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
 "krzk+dt@...nel.org" <krzk+dt@...nel.org>,
 Nicolas Prado <nfraprado@...labora.com>,
 "macpaul@...il.com" <macpaul@...il.com>,
 "wenst@...omium.org" <wenst@...omium.org>,
 Bear Wang (萩原惟德) <bear.wang@...iatek.com>,
 "linux-arm-kernel@...ts.infradead.org"
 <linux-arm-kernel@...ts.infradead.org>,
 "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
 "y.oudjana@...tonmail.com" <y.oudjana@...tonmail.com>,
 "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
 MandyJH Liu (劉人僖) <MandyJH.Liu@...iatek.com>
Subject: Re: [PATCH v3 04/10] pmdomain: mediatek: Refactor bus protection
 regmaps retrieval

Il 29/10/25 16:01, Macpaul Lin (林智斌) ha scritto:
> On Wed, 2025-10-29 at 11:56 +0100, AngeloGioacchino Del Regno wrote:
>>
> 
> [snip]
> 
>> Thanks for the logs! Getting issues on MSDC is really odd because the
>> MSDC
>> controller does *not* use nor have any power domain...
>>
>> I'll take a look at this as soon as I can, anyway.
>>
>> Thanks again,
>> Angelo
>>
>>> [    1.291055] mtk-msdc 11240000.mmc: msdc_track_cmd_data: cmd=8
>>> arg=000001AA; host->error=0x00000002
>>> [    1.292775] mtk-msdc 11240000.mmc: msdc_track_cmd_data: cmd=55
>>> arg=00000000; host->error=0x00000002
>>> [    1.294539] mtk-msdc 11240000.mmc: msdc_track_cmd_data: cmd=55
>>> arg=00000000; host->error=0x00000002
>>> [    1.296293] mtk-msdc 11240000.mmc: msdc_track_cmd_data: cmd=55
>>> arg=00000000; host->error=0x00000002
>>> ...
>>> [    1.430408] mtk-msdc 11240000.mmc: msdc_track_cmd_data: cmd=55
>>> arg=00000000; host->error=0x00000002
>>> [    1.433766] mmc0: Failed to initialize a non-removable card
>>> [   22.297240] rcu: INFO: rcu_preempt detected stalls on
>>> CPUs/tasks:
>>> [   22.298723] rcu:     6-...0: (2 ticks this GP)
>>> idle=104c/1/0x4000000000000000 softirq=45/45 fqs=37
>>> [   22.299827] rcu:     (detected by 2, t=5256 jiffies, g=-1051,
>>> q=200
>>> ncpus=8)
>>> [   22.300689] Sending NMI from CPU 2 to CPUs 6:
>>>
>>> Best regards,
>>> Macpaul Lin
>>
>>
> 
> The command retry only happens in the very beginning during linux boot.
> 
> The following rcu_preempt and cpu/task stall are keep appearing until
> poewr off. It is more like cpu not responding or runtime-PM? I've not
> try to disable any power related kernel option yet.
> 

Hello Macpaul,

I have located the source of the issue that is showing on your machine, and
I have sent a fast patch to resolve that.

Please have a look:
https://lore.kernel.org/all/20251121125212.43093-1-angelogioacchino.delregno@collabora.com/

Cheers,
Angelo

> [22649.698912] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> [22649.699687] rcu:     5-...0: (0 ticks this GP)
> idle=1b7c/1/0x4000000000000000 softirq=32/32 fqs=976599
> [22649.700835] rcu:     (detected by 1, t=5662102 jiffies, g=-1055,
> q=216 ncpus=8)
> [22649.701728] Sending NMI from CPU 1 to CPUs 5:
> [22659.701734] rcu: rcu_preempt kthread starved for 2495 jiffies! g-
> 1055 f0x0 RCU_GP_DOING_FQS(6) ->state=0x0 ->cpu=0
> [22659.703592] rcu:     Unless rcu_preempt kthread gets sufficient CPU
> time, OOM is now expected behavior.
> [22659.704746] rcu: RCU grace-period kthread stack dump:
> [22659.705386] task:rcu_preempt     state:I stack:0     pid:15
> tgid:15    ppid:2      task_flags:0x208040 flags:0x00000010
> [22659.706784] Call trace:
> [22659.707097]  __switch_to+0xf0/0x1b0 (T)
> [22659.707590]  __schedule+0x3b0/0xca8
> [22659.708039]  schedule+0x3c/0x120
> [22659.708453]  schedule_timeout+0x8c/0x130
> [22659.708956]  rcu_gp_fqs_loop+0x140/0x6c0
> [22659.709459]  rcu_gp_kthread+0x208/0x258
> [22659.709951]  kthread+0x14c/0x230
> [22659.710365]  ret_from_fork+0x10/0x20
> [22659.710824] rcu: Stack dump where RCU GP kthread last ran:
> [22659.711517] Sending NMI from CPU 1 to CPUs 0:
> [22659.712109] NMI backtrace for cpu 0
> [22659.712117] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.18.0-
> rc3-next-20251028-mtk+modified-04392-g5c921b2c5975 #1 PREEMPT
> [22659.712123] Hardware name: MediaTek Genio 1200 EVK-P1V2-EMMC (DT)
> [22659.712126] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS
> BTYPE=--)
> [22659.712130] pc : cpuidle_enter_state+0x2bc/0x720
> [22659.712137] lr : cpuidle_enter_state+0x2b8/0x720
> [22659.712141] sp : ffff800084473d00
> [22659.712143] x29: ffff800084473d00 x28: 0000000000000000 x27:
> ffff0001fef7d8c0
> [22659.712151] x26: 0000000000000001 x25: 0000149be00653eb x24:
> 0000149be01736ef
> [22659.712157] x23: 0000000000000002 x22: ffff0000c2d38880 x21:
> 0000000000000002
> [22659.712163] x20: ffff0000c2d38968 x19: ffff0001fee7e9f8 x18:
> 000000005bd3baae
> [22659.712169] x17: 000000040044ffff x16: 005000f2b5503510 x15:
> 0000000000000000
> [22659.712175] x14: ffff800084487540 x13: ffff80017b8c8000 x12:
> ffff8000816f9830
> [22659.712181] x11: 0000000000000000 x10: 0000000000000000 x9 :
> ffff8000801dc64c
> [22659.712187] x8 : 000000f2b5503510 x7 : 0000000000f0000f x6 :
> 00000000ff0ffff0
> [22659.712193] x5 : ffff80017b8c8000 x4 : 0000000000000000 x3 :
> ffff800084473c10
> [22659.712199] x2 : 000000449d287e7f x1 : ffff800084487540 x0 :
> 0000000000000000
> [22659.712205] Call trace:
> [22659.712207]  cpuidle_enter_state+0x2bc/0x720 (P)
> [22659.712212]  cpuidle_enter+0x40/0x60
> [22659.712219]  do_idle+0x208/0x298
> [22659.712226]  cpu_startup_entry+0x3c/0x50
> [22659.712232]  rest_init+0xfc/0x120
> [22659.712236]  start_kernel+0x7a4/0x920
> [22659.712243]  __primary_switched+0x88/0x98
> 
> Regards,
> Macpaul Lin
>