MIME-Version: 1.0
From: Carlo Caione <carlo@endlessm.com>
Date: Wed, 10 Jan 2018 12:15:51 +0000
Message-ID: <CAL9uMOFT3VwqHs5+wvot+dxArvhd7Bi-U5+CKhYUXjYwHcU=jg@mail.gmail.com> (sfid-20180110_131556_375099_873DCBC1)
Subject: RTL8723bu: poor signal and connection troubles
To: Jes Sorensen <Jes.Sorensen@gmail.com>
Cc: kvalo@codeaurora.org, linux-wireless@vger.kernel.org,
        mylene.josserand@free-electrons.com,
        Linux Upstreaming Team <linux@endlessm.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-wireless-owner@vger.kernel.org

Hi,
this is a follow up email to [0] since the problem was never fully
investigated / solved and I keep seeing the same problem also on my
hardware.

Also in my case the hardware is a rtl8723bt transceiver
(0x0bda:0xb720), this time shipped on the internal USB bus in a cheap
laptop branded Zyrex Sky 232.

As already reported by Mylene the problem is that using this
transceiver and the latest Linus master you can barely see any WiFi
network around and also when a WiFi network is actually seen, the
connection is impossible since the signal strength is too low to have
a reliable connection. Of course during my tests BT is off and no BT
driver is probed at all.

Using the downstream driver at [1] everything works correctly.

I tried to debug a bit the issue, in particular comparing functions
and registers related to the antenna setup (.power_on, .enable_rf,
.phy_init_antenna_selection, .phy_iq_calibrate hooks) but everything
seems pretty much the same on the two drivers (even though slightly
differences do exist).

Any idea / suggestion on how to debug this problem? I guess it's worth
to start looking at this since several platforms are being affected
now.

Cheers,

[0] https://www.spinics.net/lists/netdev/msg468028.html
[1] https://github.com/lwfinger/rtl8723bu

-- 
Carlo Caione  |  +44.7384.69.16.04  |  Endless