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

[Larry Finger]

On 07/05/2018 02:36 AM, Pkshih wrote:
> 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@xxxxxxxxxxxx> 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)
>  Â		return;
>   
>  Â	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);

This patch loses the BIT(7). Did you really mean to do that?

I now agree that this is a bug. A similar problem had been found in a few boxes 
with RTL8723BE or RTL8821AE cards, but that it might apply here completely 
slipped through the ever larger cracks in my mind.

Larry