linux-kernel - Re: [BUG] staging: r8822be: RTL8822be can't find any wireless AP

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Date:   Thu, 5 Jul 2018 07:36:02 +0000
From:   Pkshih <pkshih@...ltek.com>
To:     "Larry.Finger@...inger.net" <Larry.Finger@...inger.net>,
        "drake@...lessm.com" <drake@...lessm.com>
CC:     Shaofu <shaofu@...ltek.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dan.carpenter@...cle.com" <dan.carpenter@...cle.com>,
        "colin.king@...onical.com" <colin.king@...onical.com>,
        "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        Birming Chiu <birming@...ltek.com>,
        "kvalo@...eaurora.org" <kvalo@...eaurora.org>,
        "frank@...eralsoftwareinc.com" <frank@...eralsoftwareinc.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux@...lessm.com" <linux@...lessm.com>,
        Steven Ting <steventing@...ltek.com>,
        Tony Chuang <yhchuang@...ltek.com>,
        "arnd@...db.de" <arnd@...db.de>,
        "sgruszka@...hat.com" <sgruszka@...hat.com>,
        "jian-hong@...lessm.com" <jian-hong@...lessm.com>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>
Subject: Re: [BUG] staging: r8822be: RTL8822be can't find any wireless AP

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@...inger.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?


diff --git a/drivers/staging/rtlwifi/rtl8822be/hw.c b/drivers/staging/rtlwifi/rtl8822be/hw.c
index 7947edb239a1..88ba5b2fea6a 100644
--- a/drivers/staging/rtlwifi/rtl8822be/hw.c
+++ b/drivers/staging/rtlwifi/rtl8822be/hw.c
@@ -803,7 +803,7 @@ static void _rtl8822be_enable_aspm_back_door(struct ieee80211_hw *hw)
 		return;
 
 	pci_read_config_byte(rtlpci->pdev, 0x70f, &tmp);
-	pci_write_config_byte(rtlpci->pdev, 0x70f, tmp | BIT(7));
+	pci_write_config_byte(rtlpci->pdev, 0x70f, tmp | ASPM_L1_LATENCY << 3);
 
 	pci_read_config_byte(rtlpci->pdev, 0x719, &tmp);
 	pci_write_config_byte(rtlpci->pdev, 0x719, tmp | BIT(3) | BIT(4));
diff --git a/drivers/staging/rtlwifi/wifi.h b/drivers/staging/rtlwifi/wifi.h
index 012fb618840b..a45f0eb69d3f 100644
--- a/drivers/staging/rtlwifi/wifi.h
+++ b/drivers/staging/rtlwifi/wifi.h
@@ -88,6 +88,7 @@
 #define RTL_USB_MAX_RX_COUNT			100
 #define QBSS_LOAD_SIZE				5
 #define MAX_WMMELE_LENGTH			64
+#define ASPM_L1_LATENCY				7
 
 #define TOTAL_CAM_ENTRY				32
 

---
PK