linux-kernel - Re: [PATCH v2] serial: qcom_geni: Fix pinctrl deadlock on runtime resume

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Message-ID: <dab18f70-4017-4c06-92c1-91cfd2229540@kernel.org>
Date: Thu, 18 Sep 2025 08:58:54 +0900
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Praveen Talari <praveen.talari@....qualcomm.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Jiri Slaby <jirislaby@...nel.org>,
 Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
 Praveen Talari <quic_ptalari@...cinc.com>, linux-arm-msm@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
 alexey.klimov@...aro.org, jorge.ramirez@....qualcomm.com,
 dmitry.baryshkov@....qualcomm.com, andersson@...nel.org
Cc: psodagud@...cinc.com, djaggi@...cinc.com, quic_msavaliy@...cinc.com,
 quic_vtanuku@...cinc.com, quic_arandive@...cinc.com,
 quic_shazhuss@...cinc.com, quic_cchiluve@...cinc.com
Subject: Re: [PATCH v2] serial: qcom_geni: Fix pinctrl deadlock on runtime
 resume

On 18/09/2025 03:51, Praveen Talari wrote:
> A stall was observed in disable_irq() during
> pinctrl_pm_select_default_state(), triggered by wakeup IRQ being active
> while the UART port was not yet active. This led to a hang in
> __synchronize_irq(), as shown in the following trace:
> 
> Call trace:
>     __switch_to+0xe0/0x120
>     __schedule+0x39c/0x978
>     schedule+0x5c/0xf8
>     __synchronize_irq+0x88/0xb4
>     disable_irq+0x3c/0x4c
>     msm_pinmux_set_mux+0x508/0x644
>     pinmux_enable_setting+0x190/0x2dc
>     pinctrl_commit_state+0x13c/0x208
>     pinctrl_pm_select_default_state+0x4c/0xa4
>     geni_se_resources_on+0xe8/0x154
>     qcom_geni_serial_runtime_resume+0x4c/0x88
>     pm_generic_runtime_resume+0x2c/0x44
>     __genpd_runtime_resume+0x30/0x80
>     genpd_runtime_resume+0x114/0x29c
>     __rpm_callback+0x48/0x1d8
>     rpm_callback+0x6c/0x78
>     rpm_resume+0x530/0x750
>     __pm_runtime_resume+0x50/0x94
>     handle_threaded_wake_irq+0x30/0x94
>     irq_thread_fn+0x2c/0xa8
>     irq_thread+0x160/0x248
>     kthread+0x110/0x114
>     ret_from_fork+0x10/0x20
> 
> To fix this, wakeup IRQ setup is moved from probe to UART startup,
> ensuring it is only configured when the port is active. Correspondingly,
> the wakeup IRQ is cleared during shutdown. This avoids premature IRQ
> disable during pinctrl setup and prevents the observed stall. The probe
> and remove pathsare simplified by removing redundant wakeup IRQ handling.
> 
> Fixes: 1afa70632c39 ("serial: qcom-geni: Enable PM runtime for serial driver")
> Reported-by: Alexey Klimov <alexey.klimov@...aro.org>
> Closes: https://lore.kernel.org/all/DC0D53ZTNOBU.E8LSD5E5Z8TX@linaro.org/
> Tested-by: Jorge Ramirez <jorge.ramirez@....qualcomm.com>

Where did you receive this tag for this patch exactly?

Best regards,
Krzysztof