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Date:   Thu, 5 Jul 2018 12:32:30 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Jian-Hong Pan <jian-hong@endlessm.com>
Cc:     Pkshih <pkshih@realtek.com>,
        "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
        Tony Chuang <yhchuang@realtek.com>,
        "arnd@arndb.de" <arnd@arndb.de>,
        Steven Ting <steventing@realtek.com>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Birming Chiu <birming@realtek.com>,
        "drake@endlessm.com" <drake@endlessm.com>,
        "sgruszka@redhat.com" <sgruszka@redhat.com>,
        "kvalo@codeaurora.org" <kvalo@codeaurora.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "frank@generalsoftwareinc.com" <frank@generalsoftwareinc.com>,
        "colin.king@canonical.com" <colin.king@canonical.com>,
        "linux@endlessm.com" <linux@endlessm.com>,
        "Larry.Finger@lwfinger.net" <Larry.Finger@lwfinger.net>
Subject: Re: [BUG] staging: r8822be: RTL8822be can't find any wireless AP
Message-ID: <20180705093230.byqbk6f5ornezmka@mwanda>
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On Thu, Jul 05, 2018 at 05:26:28PM +0800, Jian-Hong Pan wrote:
> 2018-07-05 15:36 GMT+08:00 Pkshih <pkshih@realtek.com>:
> > On Wed, 2018-07-04 at 10:33 -0500, Daniel Drake wrote:
> >> On Wed, Jul 4, 2018 at 10:13 AM, Larry Finger <Larry.Finger@lwfinger.net> wrote:
> >> > We will have to agree to disagree.
> >> >
> >> > I have no idea what the vendors are doing that cause some motherboards to
> >> > need a different aspm value. What I do know is that we have had to live with
> >> > the idiocy of some vendors saving a few pennies by only including a single
> >> > antenna, rather than two, and then making a problem by miscoding the EFUSE
> >> > bit that indicates which connector is actually in use. As we have no means
> >> > that I know about to detect which boxes have the problem, a module parameter
> >> > was created, just as in this case.
> >> >
> >> > I agree that drivers should work "out of the box", but finite resources and
> >> > lack of vendor cooperation make this a goal that may not be attainable.
> >>
> >> As you touched on, the ideal situation is that Realtek solve the
> >> issue. Ping-Ke Shih is on CC and I am adding a few more contacts from
> >> the commit log. The context is that the r8822 driver fails on several
> >> platforms unless setting aspm=0 (the default is 1).
> >
> > It's hard to have all laptop or motherboards and all rtl8822be modules in my side,
> > so what I can do is to analyze the issue when user encountered.
> >
> >>
> >> https://gist.github.com/dsd/20c05f0c6d66ee2ef9bfbb17f93f18ba
> >> https://bugzilla.kernel.org/show_bug.cgi?id=199651
> >>
> >>
> >> If we don't get a timely fix from Realtek though, I think there is a
> >> key difference between the antenna selection headache and this one. In
> >> the antenna case, there isn't a good value that you can set that will
> >> work on all systems. If you change the default behaviour you will
> >> solve the issue for some users while simultanously introducing the
> >> problem on other systems that were previously fine.
> >>
> >> However in this case, it's highly likely that setting aspm=0 (off) by
> >> default would work for everyone. It has the disadvantage of using a
> >> bit more power, but especially with the indications that this issue
> >> affects a significant number of systems, I think that having the
> >> driver working out of the box everywhere is more important. The module
> >> parameter can be left in place so that unaffected users that want to
> >> save power can set aspm=1.
> >>
> >
> > I think this issue may be due to L1 latency, so below patch would be
> > helpful but not sure because I don't have the same laptop.
> > Is there anyone can help to test?
> 
> I do not know why I cannot apply this patch directly.  So, I apply
> each line manually.
> 
> However, here is a good news.  I tested this fix, and it works
> correctly on ASUS X530UN.  System can scan and get the access points
> list.  Finally, it also connects to the access point.
> Maybe, you can have a formal patch for this.
>

That's good news.  What does the "dmesg | grep r8822be" say now?

regards,
dan carpenter