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From:   Jian-Hong Pan <jhp@endlessos.org>
Date:   Fri, 10 Dec 2021 17:33:40 +0800
Message-ID: <CAPpJ_efvmPWsCFsff35GHV8Q52YvQcFr_Hs=q3RtvbfVohY+4Q@mail.gmail.com>
Subject: Re: [PATCH] rtw88: 8821c: disable the ASPM of RTL8821CE
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     Pkshih <pkshih@realtek.com>,
        Yan-Hsuan Chuang <tony0620emma@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux@endlessos.org" <linux@endlessos.org>
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Kai-Heng Feng <kai.heng.feng@canonical.com> =E6=96=BC 2021=E5=B9=B412=E6=9C=
=8810=E6=97=A5 =E9=80=B1=E4=BA=94 =E4=B8=8B=E5=8D=885:24=E5=AF=AB=E9=81=93=
=EF=BC=9A
>
> On Fri, Dec 10, 2021 at 5:00 PM Pkshih <pkshih@realtek.com> wrote:
> >
> > +Kai-Heng
> >
> > > -----Original Message-----
> > > From: Jian-Hong Pan <jhp@endlessos.org>
> > > Sent: Friday, December 10, 2021 4:17 PM
> > > To: Pkshih <pkshih@realtek.com>; Yan-Hsuan Chuang <tony0620emma@gmail=
.com>; Kalle Valo
> > > <kvalo@codeaurora.org>
> > > Cc: linux-wireless@vger.kernel.org; netdev@vger.kernel.org; linux-ker=
nel@vger.kernel.org;
> > > linux@endlessos.org; Jian-Hong Pan <jhp@endlessos.org>
> > > Subject: [PATCH] rtw88: 8821c: disable the ASPM of RTL8821CE
> > >
> > > More and more laptops become frozen, due to the equipped RTL8821CE.
> > >
> > > This patch follows the idea mentioned in commits 956c6d4f20c5 ("rtw88=
:
> > > add quirks to disable pci capabilities") and 1d4dcaf3db9bd ("rtw88: a=
dd
> > > quirk to disable pci caps on HP Pavilion 14-ce0xxx"), but disables it=
s
> > > PCI ASPM capability of RTL8821CE directly, instead of checking DMI.
> > >
> > > Buglink:https://bugzilla.kernel.org/show_bug.cgi?id=3D215239
> > > Fixes: 1d4dcaf3db9bd ("rtw88: add quirk to disable pci caps on HP Pav=
ilion 14-ce0xxx")
> > > Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
> >
> > We also discuss similar thing in this thread:
> > https://bugzilla.kernel.org/show_bug.cgi?id=3D215131
> >
> > Since we still want to turn on ASPM to save more power, I would like to
> > enumerate the blacklist. Does it work to you?
>
> Too many platforms are affected, the blacklist method won't scale.

Exactly!

> Right now it seems like only Intel platforms are affected, so can I
> propose a patch to disable ASPM when its upstream port is Intel?

I only have laptops with Intel chip now.  So, I am not sure the status
with AMD platforms.
If this is true, then "disable ASPM when its upstream port is Intel"
might be a good idea.

Jian-Hong Pan

> > If so, please help to add one quirk entry of your platform.
> >
> > Another thing is that "attachment 299735" is another workaround for cer=
tain
> > platform. And, we plan to add quirk to enable this workaround.
> > Could you try if it works to you?
>
> When the hardware is doing DMA, it should initiate leaving ASPM L1,
> correct? So in theory my workaround should be benign enough for most
> platforms.
>
> Kai-Heng
>
> >
> > Thank you
> > --
> > Ping-Ke
> >