[PATCH 2/2] wifi: mt76: mt792x: fix mt7925u USB WFSYS reset handling

[Satadru Pramanik]

After rebuilding the kernel with 7.0-rc3 and the two patches at
https://patchwork.kernel.org/project/linux-wireless/list/?series=1064695,
I can confirm that after a warm reboot booted from that kernel, the
mt7925u-based adapter is once again visible.

Thanks!

Regards,

Satadru Pramanik



On Wed, Mar 11, 2026 at 12:42 PM Satadru Pramanik <satadru at gmail.com> wrote:
>
> Hello all, I'm rebuilding this kernel one more time in case I mispatched, and will let you know shortly if a new kernel build works.
>
> Regards,
>
> Satadru
>
> On Wed, Mar 11, 2026 at 12:15 PM Nick <morrownr at gmail.com> wrote:
>>
>> > From: Sean Wang <sean.wang at mediatek.com>
>> >
>> > mt7925u uses different reset/status registers from mt7921u. Reusing the
>> > mt7921u register set causes the WFSYS reset to fail.
>> >
>> > Add a chip-specific descriptor in mt792xu_wfsys_reset() to select the
>> > correct registers and fix mt7925u failing to initialize after a warm
>> > reboot.
>> >
>> > Fixes: d28e1a48952e ("wifi: mt76: mt792x: introduce mt792x-usb module")
>> > Cc: stable at vger.kernel.org
>> > Signed-off-by: Sean Wang <sean.wang at mediatek.com>
>> > ---
>> >  drivers/net/wireless/mediatek/mt76/mt792x_regs.h |  4 ++++
>> >  drivers/net/wireless/mediatek/mt76/mt792x_usb.c  | 13 ++++++++++++-
>> >  2 files changed, 16 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
>> > index 7ddde9286861..d2a8b2b0df32 100644
>> > --- a/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
>> > +++ b/drivers/net/wireless/mediatek/mt76/mt792x_regs.h
>> > @@ -392,6 +392,10 @@
>> >  #define MT_CBTOP_RGU_WF_SUBSYS_RST     MT_CBTOP_RGU(0x600)
>> >  #define MT_CBTOP_RGU_WF_SUBSYS_RST_WF_WHOLE_PATH BIT(0)
>> >
>> > +#define MT7925_CBTOP_RGU_WF_SUBSYS_RST 0x70028600
>> > +#define MT7925_WFSYS_INIT_DONE_ADDR    0x184c1604
>> > +#define MT7925_WFSYS_INIT_DONE         0x00001d1e
>> > +
>> >  #define MT_HW_BOUND                    0x70010020
>> >  #define MT_HW_CHIPID                   0x70010200
>> >  #define MT_HW_REV                      0x70010204
>> > diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
>> > index a92e872226cf..47827d1c5ccb 100644
>> > --- a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
>> > +++ b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
>> > @@ -224,6 +224,15 @@ static const struct mt792xu_wfsys_desc mt7921_wfsys_desc = {
>> >         .need_status_sel = true,
>> >  };
>> >
>> > +static const struct mt792xu_wfsys_desc mt7925_wfsys_desc = {
>> > +       .rst_reg = MT7925_CBTOP_RGU_WF_SUBSYS_RST,
>> > +       .done_reg = MT7925_WFSYS_INIT_DONE_ADDR,
>> > +       .done_mask = U32_MAX,
>> > +       .done_val = MT7925_WFSYS_INIT_DONE,
>> > +       .delay_ms = 20,
>> > +       .need_status_sel = false,
>> > +};
>> > +
>> >  int mt792xu_dma_init(struct mt792x_dev *dev, bool resume)
>> >  {
>> >         int err;
>> > @@ -254,7 +263,9 @@ EXPORT_SYMBOL_GPL(mt792xu_dma_init);
>> >
>> >  int mt792xu_wfsys_reset(struct mt792x_dev *dev)
>> >  {
>> > -       const struct mt792xu_wfsys_desc *desc = &mt7921_wfsys_desc;
>> > +       const struct mt792xu_wfsys_desc *desc = is_mt7925(&dev->mt76) ?
>> > +                                               &mt7925_wfsys_desc :
>> > +                                               &mt7921_wfsys_desc;
>> >         u32 val;
>> >         int i;
>> >
>> > --
>> > 2.43.0
>> >
>>
>> Sean, testing results from: Satadru Pramanik <satadru at gmail.com>
>>
>> "The updated patches from
>> https://patchwork.kernel.org/project/linux-wireless/list/?series=1064695
>> do NOT work. I get the -110 error with them on a warm reboot.
>> Reverting to the kernel with the older patch restores my adapter
>> connection on a warm reboot."
>>
>> You are welcome to stop by the Github issue where this issue is being discussed:
>>
>> https://github.com/morrownr/USB-WiFi/issues/688#
>>
>> Nick