Re: [PATCH v7 03/27] phy: rockchip: usbdp: Do not lose USB3 PHY status

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Preserving the PHY status across mode changes exposes a permanent power leak if the USB driver exits while a 4-lane DisplayPort is active.
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commit eb97195758d636e8b97b5ffd69c0022de4826241
Author: Sebastian Reichel <sebastian.reichel@collabora.com>

phy: rockchip: usbdp: Do not lose USB3 PHY status

By default DWC3 requests the USB3 PHY once and keeps it enabled. When
DisplayPort is being requested later on, a mode change is needed which
re-initializes the PHY. This patch removes the clearing of the status variable
during re-initialization to ensure USB3 tracking information isn't lost.

> diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> index a5ffdf7a6e76b..12dfdd470a782 100644
> --- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
> +++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> @@ -1008,7 +1008,6 @@ static int rk_udphy_power_on(struct rk_udphy *udphy, u8 mode)
>  			rk_udphy_u3_port_disable(udphy, false);
>  		udphy->mode_change = false;
>  	} else if (udphy->mode_change) {
> -		udphy->status = UDPHY_MODE_NONE;

[Severity: Medium]
Does this change introduce a potential power and clock leak when the USB
driver unbinds or suspends?

By preserving the UDPHY_MODE_USB bit in udphy->status across mode changes,
the status bit remains active while udphy->mode might be set to DP-only
(for example, when a 4-lane DisplayPort adapter is connected).

If rk_udphy_usb3_phy_exit() is called while the mode is DP-only, the early
mode check will trigger because udphy->mode lacks UDPHY_MODE_USB.
This causes an early return, skipping the call to rk_udphy_power_off()
and leaving the UDPHY_MODE_USB bit stranded in udphy->status.

Later, when DisplayPort is powered off and rk_udphy_power_off() clears the
UDPHY_MODE_DP bit, the status will drop to UDPHY_MODE_USB instead of
UDPHY_MODE_NONE. Could this bypass the final rk_udphy_disable() call,
leaving the PHY powered on and leaking the clock references indefinitely?

>  		if (udphy->mode == UDPHY_MODE_DP)
>  			rk_udphy_u3_port_disable(udphy, true);
>

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Sashiko AI review · https://sashiko.dev/#/patchset/20260625-rockchip-usbdp-cleanup-v7-0-38eb3cf654fd@collabora.com?part=3