Re: [PATCH 17/21] soundwire: amd: Resume manager before hardware teardown in amd_sdw_manager_remove()

[Mukunda,Vijendar]

On 10/30/26 16:16, Lee Jones wrote:
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>
> amd_sdw_manager_remove() calls pm_runtime_disable() and immediately
> accesses MMIO registers in amd_disable_sdw_interrupts() and
> amd_disable_sdw_manager() without waking the device if it is
> runtime-suspended.
>
> Call pm_runtime_get_sync() before disabling runtime PM and balance the
> usage count with pm_runtime_put_noidle() so the controller is awake
> during teardown.
>
> Fixes: 81ff58ff71ad ("soundwire: amd: add runtime pm ops for AMD SoundWire manager driver")
> Closes: https://sashiko.dev/#/bug/linux-dad4d803-06a7-473d-829d-66860776f4d6
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
> ---
>   drivers/soundwire/amd_manager.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/soundwire/amd_manager.c b/drivers/soundwire/amd_manager.c
> index 2e1038ea0f36..1d8a08bda261 100644
> --- a/drivers/soundwire/amd_manager.c
> +++ b/drivers/soundwire/amd_manager.c
> @@ -1196,7 +1196,9 @@ static void amd_sdw_manager_remove(struct platform_device *pdev)
>          struct amd_sdw_manager *amd_manager = dev_get_drvdata(&pdev->dev);
>          int ret;
>
> +       pm_runtime_get_sync(&pdev->dev);
>          pm_runtime_disable(&pdev->dev);
> +       pm_runtime_put_noidle(&pdev->dev);
The SoundWire manager is a child platform device of the ACP PCI
device and does not have a dedicated BAR. Its MMIO is mapped through
the parent ACP PCI device's address space, which remains valid and
accessible for the lifetime of the parent device.

Runtime-suspending the SoundWire manager child device does not unmap
or gate that MMIO region. As long as the parent ACP PCI device is
alive — which it is during child device teardown — MMIO access is
always safe, regardless of the child's runtime PM state.

The described scenario cannot occur on this hardware. Please drop
this patch.
>          cancel_work_sync(&amd_manager->amd_sdw_irq_thread);
>          cancel_work_sync(&amd_manager->amd_sdw_work);
>          amd_disable_sdw_interrupts(amd_manager);
> --
> 2.56.0.317.g454f8302e1-goog