Message-ID: <546E6C62.9010808@lwfinger.net> (sfid-20141120_233416_081836_110E7AE6)
Date: Thu, 20 Nov 2014 16:34:10 -0600
From: Larry Finger <Larry.Finger@lwfinger.net>
MIME-Version: 1.0
To: Catalin Iacob <iacobcatalin@gmail.com>,
	linux-wireless@vger.kernel.org
Subject: Re: rtl8192ce 3.18 regression scan doesn't find any APs
References: <CAHg_5go+AZTytHq7OyoV_r35sj2wW0OwgBq+sm8R+zJbOXiYcA@mail.gmail.com>
In-Reply-To: <CAHg_5go+AZTytHq7OyoV_r35sj2wW0OwgBq+sm8R+zJbOXiYcA@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Sender: linux-wireless-owner@vger.kernel.org

On 11/20/2014 02:10 PM, Catalin Iacob wrote:
> Since the 3.18 merge window my wireless card cannot find any access
> point (tested with both NetworkManager and sudo /usr/sbin/iw dev
> wlp2s0 scan). More precisely, in 3.18-rc1 I got the oops described at
> http://marc.info/?l=linux-wireless&m=141324391807122&w=2. Sometime
> after rc1 Larry fixed this but when I tested again I found that scan
> doesn't work (tested 3.18-rc3 and just now 3.18-rc5).
>
> According to lspci -nn my hardware is:
> 02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd.
> RTL8188CE 802.11b/g/n WiFi Adapter [10ec:8176] (rev 01)
>
> If I grep dmesg for rtl, for 3.17 which works I get:
> [   31.208206] rtl8192ce:_rtl92ce_read_chip_version():<0-0> Chip
> Version ID: B_CHIP_88C
> [   31.219973] rtl8192ce: Using firmware rtlwifi/rtl8192cfw.bin
> [   31.861478] ieee80211 phy0: Selected rate control algorithm 'rtl_rc'
> [   31.865655] rtlwifi: wireless switch is on
> [   31.872019] rtl8192ce 0000:02:00.0 wlp2s0: renamed from wlan0
> [   41.428487] rtl8192ce 0000:02:00.0 wlp2s0: disabling HT as WMM/QoS
> is not supported by the AP
> [   41.428499] rtl8192ce 0000:02:00.0 wlp2s0: disabling VHT as WMM/QoS
> is not supported by the AP
>
> 3.18 says:
> [   29.213829] rtl8192ce:_rtl92ce_read_chip_version():<0-0> Chip
> Version ID: B_CHIP_88C
> [   29.230599] rtl8192ce: Using firmware rtlwifi/rtl8192cfw.bin
> [   29.330232] ieee80211 phy0: Selected rate control algorithm 'rtl_rc'
> [   29.332250] rtlwifi: rtlwifi: wireless switch is on
> [   29.339416] rtl8192ce 0000:02:00.0 wlp2s0: renamed from wlan0
> [  344.942070] rtl8192ce:rtl92ce_get_hw_reg():<0-0> switch case not processed
>
> I added some debug prints and the last line comes from core.c,
> rtl_op_stop which calls get_hw_reg with HAL_DEF_WOWLAN. This happens
> indeed when I untick Enable wireless in NetworkManager. I assume it's
> not related to the more serious scan issue.
>
> How can I help with debugging this?

I do not believe that "switch case not processed" is serious, but I will check it.

I have reproduced the problem, but I do not yet know the fix. Please file a bug 
report at bugzilla.kernel.org on this problem. Be sure to mark it as a 
regression, and assign it to me. When I find the fix, being able to cite the bug 
report will help get a last-minute patch into 3.18.

Larry