Re: [PATCH] Bluetooth: Properly disable remote wakeup for MT7922/MT7925 on Ryzen platform
Rong Zhang
i at rong.moe
Tue Jun 30 12:15:19 PDT 2026
Hi Luiz,
于 2026年7月1日 GMT+08:00 02:13:39，Luiz Augusto von Dentz <luiz.dentz at gmail.com> 写道：
>Hi Rong,
>
>On Mon, Jun 29, 2026 at 11:28 AM Rong Zhang <i at rong.moe> wrote:
>>
>> It is reported that a remote wakeup could cause MT7922/MT7925's btusb
>> interface completely unresponsive. Resetting the xHCI root hub doesn't
>> help at all, and recovering from such a state needs a power cycle.
>>
>> All reports seen to be relevant to Ryzen-based laptops. These NICs are
>> usually used as OEM components thanks to some sort of reference designs.
>>
>> Their popularity on other platforms is unclear. While there is still a
>> chance that the quirk may exist on other platforms, be cautious and only
>> apply the quirk on AMD platforms for the time being.
>>
>> Meanwhile, though device_set_wakeup_capable(false) is the correct fix
>> for other NICs with fake remote wakeup capabilities, doing so for
>> MT7922/MT7925 effectively prevents it from being used as wakeup
>> sources as per userspace requests. Hence, return -EBUSY on runtime
>> suspend to prevent the interface from being autosuspended while it's
>> still opened, which has the same effect as
>> device_set_wakeup_capable(false), since disabling remote wakeup simply
>> causes the USB core to gate runtime autosuspend as well due to
>> needs_remote_wakeup == 1. The interface can be safely autosuspended as
>> long as remote wakeup is disabled, i.e., after closing the HCI device.
>>
>> Specifically, the interface may still take the advantage of remote
>> wakeup in order to wake up the system from sleep if userspace has
>> enabled it as a wakeup source.
>>
>> Fixes: e31d761628ad ("Bluetooth: btmtk: Disable remote wakeup for MT7922/MT7925")
>> Signed-off-by: Rong Zhang <i at rong.moe>
>> ---
>> drivers/bluetooth/btmtk.c | 10 ---------
>> drivers/bluetooth/btusb.c | 57 +++++++++++++++++++++++++++++++++++++++++++----
>> 2 files changed, 53 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
>> index 02a96342e964..4614434dd57b 100644
>> --- a/drivers/bluetooth/btmtk.c
>> +++ b/drivers/bluetooth/btmtk.c
>> @@ -1381,16 +1381,6 @@ int btmtk_usb_setup(struct hci_dev *hdev)
>> break;
>> case 0x7922:
>> case 0x7925:
>> - /*
>> - * A remote wakeup could cause the device completely unresponsive, and
>> - * recovering from such a state needs a power cycle.
>> - *
>> - * Since the remote wakeup capability is super broken, just disable it
>> - * to get rid of the troubles. The device can still be autosuspended
>> - * when the bluetooth interface is closed.
>> - */
>> - device_set_wakeup_capable(&btmtk_data->udev->dev, false);
>> - fallthrough;
>> case 0x7961:
>> case 0x7902:
>> case 0x6639:
>> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
>> index 08c0a99a62c5..023ae782f41a 100644
>> --- a/drivers/bluetooth/btusb.c
>> +++ b/drivers/bluetooth/btusb.c
>> @@ -6,6 +6,7 @@
>> * Copyright (C) 2005-2008 Marcel Holtmann <marcel at holtmann.org>
>> */
>>
>> +#include <linux/cpufeature.h>
>> #include <linux/dmi.h>
>> #include <linux/module.h>
>> #include <linux/usb.h>
>> @@ -957,6 +958,7 @@ struct qca_dump_info {
>> #define BTUSB_USE_ALT3_FOR_WBS 15
>> #define BTUSB_ALT6_CONTINUOUS_TX 16
>> #define BTUSB_HW_SSR_ACTIVE 17
>> +#define BTUSB_WAKEUP_BROKEN 18
>>
>> struct btusb_data {
>> struct hci_dev *hdev;
>> @@ -2936,10 +2938,20 @@ static int btusb_send_frame_mtk(struct hci_dev *hdev, struct sk_buff *skb)
>> }
>> }
>>
>> +static inline bool platform_is_ryzen(void)
>> +{
>> +#ifdef CONFIG_X86
>> + return boot_cpu_has(X86_FEATURE_ZEN);
>> +#else
>> + return false;
>> +#endif
>> +}
>> +
>> static int btusb_mtk_setup(struct hci_dev *hdev)
>> {
>> struct btusb_data *data = hci_get_drvdata(hdev);
>> struct btmtk_data *btmtk_data = hci_get_priv(hdev);
>> + int err;
>>
>> /* MediaTek WMT vendor cmd requiring below USB resources to
>> * complete the handshake.
>> @@ -2956,7 +2968,29 @@ static int btusb_mtk_setup(struct hci_dev *hdev)
>> btusb_mtk_claim_iso_intf(data);
>> }
>>
>> - return btmtk_usb_setup(hdev);
>> + err = btmtk_usb_setup(hdev);
>> + if (err)
>> + return err;
>> +
>> + switch (btmtk_data->dev_id) {
>> + case 0x7922:
>> + case 0x7925:
>> + /*
>> + * All reports seen to be relevant to Ryzen-based laptops. These
>> + * NICs are usually used as OEM components thanks to some sort
>> + * of reference designs.
>> + *
>> + * Their popularity on other platforms is unclear. While there
>> + * is still a chance that the quirk may exist on other
>> + * platforms, be cautious and only apply the quirk on AMD
>> + * platforms for the time being.
>> + */
>
>Is this going to be a reliable way to detect if wakeup is broken or
>not? Since USB is a bus capable of hotplug, this check would block not
>only internal/built-in controllers with the above IDs but also those
>plugged via external ports if the CPU happens to be of the ZEN
>familly.
Hmm, it seems that we can detect the device's position by comparing its parent and its bus. We can additionally make it further by checking against the root hub's VID. In this manner we should be able to drop the boot_cpu_has() check too.
I will try and send a v2.
Thanks,
Rong
>
>> + if (platform_is_ryzen())
>> + set_bit(BTUSB_WAKEUP_BROKEN, &data->flags);
>> + break;
>> + }
>> +
>> + return 0;
>> }
>>
>> static int btusb_mtk_shutdown(struct hci_dev *hdev)
>> @@ -4532,11 +4566,26 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
>>
>> BT_DBG("intf %p", intf);
>>
>> - /* Don't auto-suspend if there are connections or discovery in
>> - * progress; external suspend calls shall never fail.
>> + /*
>> + * It is reported that remote wakeup events could sometimes cause some
>> + * adapters completely unresponsive. Resetting the xHCI root hub doesn't
>> + * help at all, and recovering from such a state needs a power cycle.
>> + * Since disabling remote wakeup simply causes the USB core to gate
>> + * runtime autosuspend as well due to needs_remote_wakeup == 1, let's do
>> + * this ourselves to make our life easier. The interface can be safely
>> + * autosuspended as long as remote wakeup is disabled, i.e., after
>> + * closing the HCI device.
>> + *
>> + * Don't auto-suspend if there are connections or discovery in progress.
>> + *
>> + * External suspend calls shall never fail. Specifically, a device with
>> + * broken remote wakeup may still take the advantage of remote wakeup in
>> + * order to wake up the system from sleep if userspace has enabled it as
>> + * a wakeup source.
>> */
>> if (PMSG_IS_AUTO(message) &&
>> - (hci_conn_count(data->hdev) || hci_discovery_active(data->hdev)))
>> + ((test_bit(BTUSB_WAKEUP_BROKEN, &data->flags) && data->intf->needs_remote_wakeup) ||
>> + hci_conn_count(data->hdev) || hci_discovery_active(data->hdev)))
>> return -EBUSY;
>>
>> if (data->suspend_count++)
>>
>> ---
>> base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
>> change-id: 230ba8c9-btmtk-ryzen-remote-wakeup-055a407682ef
>>
>> Thanks,
>> Rong
>>
>
>
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