Re: [PATCH net-next v5 9/9] r8152: enable UPS for RTL8157 and RTL8159 QFN68

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- [Medium] If the new backup-restore poll in r8157_ups_en(tp, false)
  times out during runtime resume on RTL_VER_16 or RTL_VER_17_QFN68, the…

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r8152: enable UPS for RTL8157 and RTL8159 QFN68

This patch adds r8157_ups_en() and calls it from rtl8157_runtime_enable()
for RTL_VER_16 and RTL_VER_17_QFN68. When UPS is disabled and PCUT_STATUS
is set, the new disable path polls for backup-restore to finish. It also
extends r8156_ups_flags() with per-speed EEE flags and the 5G/10G speed
encodings.

> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index b2e4b071d84f0..baac964fea80f 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c

[ ... ]

> @@ -4486,6 +4524,49 @@ static void r8156_ups_en(struct r8152 *tp, bool enable)
>  	}
>  }
>  
> +static void r8157_ups_en(struct r8152 *tp, bool enable)
> +{
> +	if (enable) {
> +		r8156_ups_flags(tp);
> +
> +		ocp_byte_set_bits(tp, MCU_TYPE_USB, USB_POWER_CUT,
> +				  UPS_EN | USP_PREWAKE | PHASE2_EN);
> +
> +		ocp_byte_set_bits(tp, MCU_TYPE_USB, USB_MISC_2,
> +				  UPS_FORCE_PWR_DOWN);
> +	} else {
> +		ocp_byte_clr_bits(tp, MCU_TYPE_USB, USB_POWER_CUT,
> +				  UPS_EN | USP_PREWAKE);
> +
> +		ocp_byte_clr_bits(tp, MCU_TYPE_USB, USB_MISC_2,
> +				  UPS_FORCE_PWR_DOWN);
> +
> +		if (ocp_read_word(tp, MCU_TYPE_USB, USB_MISC_0) & PCUT_STATUS) {
> +			u32 ocp_data;
> +			int ret;
> +
> +			ret = read_poll_timeout(ocp_read_word, ocp_data,
> +						ocp_data & BACKUP_RESTRORE, 200,
> +						20000, false, tp, MCU_TYPE_USB,
> +						USB_GPHY_CTRL);
> +			if (ret) {
> +				rtl_set_inaccessible(tp);
> +				dev_err(&tp->intf->dev,
> +					"backup-restore timed out\n");
> +				return;
> +			}

[Severity: Medium]
If this read_poll_timeout() times out during a runtime resume on
RTL_VER_16 or RTL_VER_17_QFN68, does anything recover the device?

The path looks like this:

rtl8152_resume()
  rtl8152_runtime_resume()
    tp->rtl_ops.autosuspend_en(tp, false)
      rtl8157_runtime_enable(tp, false)
        r8157_ups_en(tp, false)
          rtl_set_inaccessible(tp)

r8157_ups_en() returns void, so rtl8152_runtime_resume() keeps going and
returns 0. The reset fallback in rtl8152_resume() skips the runtime case:

	if (!runtime_resume && test_bit(RTL8152_INACCESSIBLE, &tp->flags))
		usb_reset_device(tp->udev);

The register reads in the poll succeeded, so r8152_control_msg() never
queued a reset. After that, every access returns early before
r8152_control_msg() gets to its reset logic:

	if (test_bit(RTL8152_INACCESSIBLE, &tp->flags))
		return -ENODEV;

r8152_submit_rx(), the interrupt callback and bottom_half() also return
early while the flag is set.

Would the interface then stay unusable until some unrelated reset, such
as rtl8152_tx_timeout() when TX traffic stalls, or a replug? An idle
interface would get neither.

Before this patch these chips never entered UPS on runtime suspend, so
this resume failure looks new.

Could this path queue a reset, or otherwise pass the error back, in the
runtime resume case?

> +
> +			/* clear USB fw_ver_reg */
> +			ocp_write_byte(tp, MCU_TYPE_USB, USB_FW_USB_VER, 0);
> +
> +			tp->rtl_ops.hw_phy_cfg(tp);
> +
> +			rtl8152_set_speed(tp, tp->autoneg, tp->speed,
> +					  tp->duplex, tp->advertising);
> +		}
> +	}
> +}

[ ... ]

> @@ -4644,9 +4725,28 @@ static void rtl8157_runtime_enable(struct r8152 *tp, bool enable)

[ ... ]

>  	} else {
>  		r8153_queue_wake(tp, false);
>  		rtl_runtime_suspend_enable(tp, false);
> +
> +		switch (tp->version) {
> +		case RTL_VER_16:
> +		case RTL_VER_17_QFN68:
> +			r8157_ups_en(tp, false);
> +			break;
> +		default:
> +			break;
> +		}
> +
>  		r8157_u2p3en(tp, true);
>  		if (tp->udev->speed >= USB_SPEED_SUPER)
>  			r8153b_u1u2en(tp, true);
>  	}

[ ... ]

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Sashiko AI review · https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20261001091144.28191-1-nic_swsd%40realtek.com