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Date:      Sun, 22 Jul 2018 18:07:15 -0400
From:      Farhan Khan <khanzf@gmail.com>
To:        Kevin Lo <kevlo@freebsd.org>, avos@freebsd.org, freebsd-wireless@freebsd.org
Subject:   Re: Where is rtwn(4) scan failing
Message-ID:  <CAFd4kYBqRLxtZwkK61Q6D=xRQMucKyz2AM19SZ6XhBXFQhTqxg@mail.gmail.com>
In-Reply-To: <CAFd4kYCNDTjTbPRxoU_pEbV1sBczhJn6NjfPSgt2c7HsfG3nGQ@mail.gmail.com>
References:  <CAFd4kYCNDTjTbPRxoU_pEbV1sBczhJn6NjfPSgt2c7HsfG3nGQ@mail.gmail.com>

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On Fri, Jul 6, 2018 at 5:35 PM, Farhan Khan <khanzf@gmail.com> wrote:
> Hi Kevin, Andriy, et al,
>
> As you know, I am working on expanding rtwn(4) to include the
> rtl8188ee driver. It appears that net80211(4) performs a scan before
> associating to a BSS, so I am working on scanning. When I run
> `ifconfig wlan0 scan`, sta_pick_bss() returns immediately without any
> listed networks suggesting that whatever happens in the driver is
> failing.
>
> It appears that the scanning method begins at rtwn_scan_start(). Using
> dtrace and manually tracing the source, I identified that the kernel
> executes the following non-net80211(4) methods:
>
> * rtwn_raw_xmit
> * r92c_fill_tx_desc_raw
> * r88ee_tx_setup_macid
> * r88ee_tx_setup_hwseq
> * rtwn_pci_tx_start_frame
> * r92ce_copy_tx_desc
> * r92ce_tx_postsetup
> * r92ce_dump_tx_desc
>
> First, can you please provide a conceptual overview of what is
> happening in these functions?
>
> Second, I am not certain which (or more than one?) are failing to
> function properly with the new driver. Any ideas?
>
> As you know, I am using the Linux rtlwifi code as documentation, but
> their code is extremely difficult to read. I suspect that FreeBSD's
> r92c_fill_tx_desc_raw is Linux's rtl92ce_tx_fill_desc, but as I said,
> the Linux code is extremely difficult to trace through. The rtl8188ee
> equivalent is rtl88ee_tx_fill_desc. I only noticed 1 difference thus
> far which I do not understand yet.
>
> I suspect somewhere a value is set to 0x1f which should be 0x3f or
> something of this nature. I was stuck on Rx for around some 6 months
> and while eventually got it, it would be nice to be a little more
> efficient with Tx :)
>
> Again, any assistance is greatly appreciated.
> Thank you!
> --
> Farhan Khan
> PGP Fingerprint: B28D 2726 E2BC A97E 3854 5ABE 9A9F 00BC D525 16EE

Hi all,

I am still stuck on this and have made no progress in the past few
weeks. Does anyone have any ideas?
I could really use some assistance and have not heard anything back from anyone.

"ifconfig wlan0 scan" immediately returns with no scan results.

Where might the issues reside?
Please please provide guidance.

Thanks

--
Farhan Khan
PGP Fingerprint: B28D 2726 E2BC A97E 3854 5ABE 9A9F 00BC D525 16EE



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