Received-SPF: pass (google.com: domain of linux-wireless+bounces-2127-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Precedence: bulk
MIME-Version: 1.0
References: <36972ff5-0c48-4bd2-8f9a-9649bfa24225@lexina.in>
 <11c7333aee0d45fd9fbfc65f6e2a3aa2@realtek.com> <216e8522-fa56-4d54-ae32-74c6008a2075@lexina.in>
 <0969b1ca039e423dbcc41de18db023c6@realtek.com> <cc54a8b2-2fea-406c-8d4a-24ddfd34f983@lexina.in>
 <0be52db8941c4e609bfda6c69a14184e@realtek.com> <CAFBinCDT2Pj_BYqCtk+i7y8LPU2qwah-4Scdq29ONBqs3wt0pQ@mail.gmail.com>
 <8192e59807e14525b821317a5f550ea4@realtek.com> <CAFBinCBf2XM-W8-_YEGXydy4kLHHar7Fv5=GoKddjE9f0hTkAw@mail.gmail.com>
 <e4ccf840-a38c-455e-af75-5f4db8a97702@lexina.in>
In-Reply-To: <e4ccf840-a38c-455e-af75-5f4db8a97702@lexina.in>
From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date: Wed, 17 Jan 2024 21:48:54 +0100
Message-ID: <CAFBinCAsuCqEVJq-No-+D-T644mQ-qsez-Di-=s9gricOrk3wQ@mail.gmail.com>
Subject: Re: rtw88: rtl8822cs AP mode not working
To: Viacheslav <adeep@lexina.in>
Cc: Ping-Ke Shih <pkshih@realtek.com>, 
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>, 
	=?UTF-8?Q?Jernej_=C5=A0krabec?= <jernej.skrabec@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Hi Viacheslav,

On Wed, Jan 17, 2024 at 10:48=E2=80=AFAM Viacheslav <adeep@lexina.in> wrote=
:
[...]
> > 3) Has anybody tried AP mode with rtw88 on a (supported) USB chipset?
> > If my thought (from #2) is correct then AP mode would show the same
> > problems there.
>
> I have USB RTL8821CU. It works in AP mode:
Thank you - this helps a lot as it narrows down the problem a lot!
If RTL8821CU works in AP mode the problem must be one of:
- a bug in sdio.c (in my opinion this is the most likely cause -
starting point: rtw_sdio_write_data_rsvd_page())
- some missing bits that are only SDIO relevant (in other words: code
that hasn't made it from the downstream driver into rtw88 yet)
- chipset specific differences (RTL8821C vs RTL8822C)
- a bug in the existing code that only affects SDIO cards (but doesn't
affect PCI / USB chips)
- a combination of any of those issues

I won't have time to look into this any further before the weekend.
Once I have more findings I'll let you know.

[...]
> > 4) Viacheslav, I think you previously mentioned that you did a bit of
> > work with the downstream driver.
> > It would be awesome if you could also take a look at the rtw88 and
> > downstream driver code and start comparing them (logic that's
> > different or completely missing from rtw88 is suspicious).
> >
>
> I made some minor fixes to restore functionality after kernel updates.
> But in this case, I will need help to understand where and how to start
> figuring this out.
The last rtw88 sdio bug fixes also only required changing only a few lines =
each.
As always: the tricky part is finding out what to change (without
breaking something else) :-)

> Moreover, we've encountered another problem: after two or three days the
> client WiFi connection stops working, the network interface loses its
> DHCP address, and consequently nothing else works.
Can you please confirm (to avoid any misunderstanding) that:
- this is in STA mode (meaning: RTL8822CS is connected to another AP)
- "loses it's DHCP address" means traffic stops flowing, even DHCP
renew is not working anymore
- (does restarting the interface: ip link set down ...; ip link set up
... work?)


Best regards,
Martin