Re: [PATCH wireless-next] wifi: mt7601u: add vnd_reset parameter to fix probe failure on Tenda U2

[Bitterblue Smith <rtl8821cerfe2@gmail.com>]

On 06/09/2026 23:20, Herman Semenoff wrote:
> From c03d73d37df440d0046d68406fde2aa1f62fe0d1 Mon Sep 17 00:00:00 2001
> From: Herman Semenoff <GermanAizek@aizekgroup.ru>
> Date: Thu, 3 Sep 2026 07:14:32 +0300
> Subject: [PATCH wireless-next] wifi: mt7601u: add vnd_reset parameter
> to fix probe failure on Tenda U2
> 
> On certain MT7601U adapters, such as Tenda U2 and other newer hardware
> revisions, driver initialization consistently fails during probe with
> vendor request timeouts (-110 / -ETIMEDOUT):
> 
>     mt7601u 3-14:1.0: ASIC revision: 76010001 MAC revision: 76010500
>     mt7601u 3-14:1.0: Firmware Version: 0.1.00 Build: 7640
>     mt7601u 3-14:1.0: Vendor request req:07 off:09a8 failed:-110
>     mt7601u 3-14:1.0: Vendor request req:02 off:09a8 failed:-110
>     mt7601u 3-14:1.0: Vendor request req:07 off:0734 failed:-110
>     mt7601u 3-14:1.0: Vendor request req:42 off:0230 failed:-110
>     mt7601u 3-14:1.0: probe with driver mt7601u failed with error -110
> 
> The failure occurs because mt7601u_load_firmware() unconditionally calls
> mt7601u_vendor_reset() (MT_VEND_DEV_MODE_RESET) before uploading firmware
> chunks. On these devices, issuing this vendor reset leaves the internal
> MCU / FCE DMA engine in an unresponsive state after the first firmware
> URB is submitted. As a result, reading MT_TX_CPU_FROM_FCE_CPU_DESC_IDX
> (0x09a8) immediately times out.
> 
> Introduce a boolean module parameter 'vnd_reset' (default: false) to
> make this vendor reset optional. When the vendor reset is skipped,
> firmware upload succeeds and the wireless interface initializes normally.
> 

Hi,

I don't think a new module parameter will be accepted.

You could just delete the vendor reset. The devices which currently work
with the vendor reset will probably still work without it:

https://lore.kernel.org/linux-wireless/62826d1d-9cef-4eff-b6c5-5ed11405a482@gmail.com/

> Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1716301
> Link: https://www.opena.tv/viewtopic.php?t=63919
> Link: https://askubuntu.com/questions/1418850/the-problem-with-wi-fi-u2
> Link: https://bbs.archlinux.org/viewtopic.php?id=224859
> Link: https://reddit.com/r/archlinux/comments/1d6dfv5/mt7601u_usb_wifi_not_working/
> Signed-off-by: Herman Semenoff <GermanAizek@aizekgroup.ru>
> ---
> This patch is based on linux-next (tag: next-20260904, commit af5f12805e5c)
> and targets the wireless-next tree.
> 
> Note: Alternatively, if maintainers prefer to avoid adding a module
> parameter and can confirm that mt7601u_vendor_reset() is not required
> on any supported hardware, the vendor reset call could instead be dropped
> entirely.
> 
>  drivers/net/wireless/mediatek/mt7601u/mcu.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt7601u/mcu.c
> b/drivers/net/wireless/mediatek/mt7601u/mcu.c
> index bad6ca821400..c7c5bd9bb9df 100644
> --- a/drivers/net/wireless/mediatek/mt7601u/mcu.c
> +++ b/drivers/net/wireless/mediatek/mt7601u/mcu.c
> @@ -10,6 +10,7 @@
>  #include <linux/delay.h>
>  #include <linux/usb.h>
>  #include <linux/skbuff.h>
> +#include <linux/moduleparam.h>
> 
>  #include "mt7601u.h"
>  #include "dma.h"
> @@ -21,6 +22,10 @@
>  #define MCU_FW_URB_SIZE (MCU_FW_URB_MAX_PAYLOAD + 12)
>  #define MCU_RESP_URB_SIZE 1024
> 
> +static bool vnd_reset;
> +module_param(vnd_reset, bool, 0644);
> +MODULE_PARM_DESC(vnd_reset, "Perform vendor reset during firmware
> upload (default: false)");
> +
>  static inline int firmware_running(struct mt7601u_dev *dev)
>  {
>   return mt7601u_rr(dev, MT_MCU_COM_REG0) == 1;
> @@ -459,8 +464,10 @@ static int mt7601u_load_firmware(struct mt7601u_dev *dev)
>   mt7601u_wr(dev, 0x94c, 0);
>   mt7601u_wr(dev, MT_FCE_PSE_CTRL, 0);
> 
> - mt7601u_vendor_reset(dev);
> - msleep(5);
> + if (vnd_reset) {
> + mt7601u_vendor_reset(dev);
> + usleep_range(5000, 10000);
> + }
> 
>   mt7601u_wr(dev, 0xa44, 0);
>   mt7601u_wr(dev, 0x230, 0x84210);