Re: [PATCH V1 09/20] accel/amdxdna: Add context switch hysteresis with debugfs control

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] amdxdna: ignoring timeout in aie4_config_fw() leaves device wedged
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commit 22f93820c29f525444ddc497eafd8728678db445
Author: David Zhang <yidong.zhang@amd.com>
accel/amdxdna: Add context switch hysteresis with debugfs control

This commit adds aie4_set_ctx_hysteresis() to configure the AIE4 context
switch hysteresis timeout via the SET_RUNTIME_CONFIG message, and it exposes a
debugfs node to change the timeout at runtime.

> diff --git a/drivers/accel/amdxdna/aie4_pci.c b/drivers/accel/amdxdna/aie4_pci.c
> index 95e682a3a4b75..60348ec5bc53b 100644
> --- a/drivers/accel/amdxdna/aie4_pci.c
> +++ b/drivers/accel/amdxdna/aie4_pci.c
[ ... ]
> @@ -325,6 +327,20 @@ int aie4_restore_power_mode(struct amdxdna_dev_hdl *ndev)
>  	return aie4_msg_set_power_mode(ndev, ndev->pw_mode);
>  }
>  
> +static int aie4_config_fw(struct amdxdna_dev_hdl *ndev)
> +{
> +	int ret;
> +
> +	ret = aie4_attach_work_buffer(ndev);
> +	if (ret)
> +		return ret;
> +
> +	/* Best-effort tuning knob; failure is warned inside and does not fail hw start */
> +	aie4_set_ctx_hysteresis(ndev, ndev->ctx_switch_hysteresis_us);

[Severity: Medium]
Does ignoring the return value of aie4_set_ctx_hysteresis() leave the device
in a wedged state if a timeout occurs?

If the firmware hangs or times out while processing the context hysteresis
configuration message during initialization or resume, aie_send_mgmt_msg_wait()
returns -ETIME and destroys the management channel.

Because aie4_config_fw() explicitly ignores all errors to treat the knob as
"best-effort", initialization will falsely succeed even if the management
channel has been destroyed. This leaves the device silently unusable. Is there
a way to distinguish between non-fatal errors and fatal timeouts to prevent
the probe from succeeding with a destroyed management channel?

> +
> +	return 0;
> +}
> +
>  static int aie4_pf_hw_start(struct amdxdna_dev_hdl *ndev)
>  {
>  	int ret;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260930033233.1727265-1-yidong.zhang@amd.com?part=9