netdev - Re: [PATCH] rtw88: 8821c: disable the ASPM of RTL8821CE

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Date:   Fri, 10 Dec 2021 17:23:53 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Pkshih <pkshih@...ltek.com>
Cc:     Jian-Hong Pan <jhp@...lessos.org>,
        Yan-Hsuan Chuang <tony0620emma@...il.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux@...lessos.org" <linux@...lessos.org>
Subject: Re: [PATCH] rtw88: 8821c: disable the ASPM of RTL8821CE

On Fri, Dec 10, 2021 at 5:00 PM Pkshih <pkshih@...ltek.com> wrote:
>
> +Kai-Heng
>
> > -----Original Message-----
> > From: Jian-Hong Pan <jhp@...lessos.org>
> > Sent: Friday, December 10, 2021 4:17 PM
> > To: Pkshih <pkshih@...ltek.com>; Yan-Hsuan Chuang <tony0620emma@...il.com>; Kalle Valo
> > <kvalo@...eaurora.org>
> > Cc: linux-wireless@...r.kernel.org; netdev@...r.kernel.org; linux-kernel@...r.kernel.org;
> > linux@...lessos.org; Jian-Hong Pan <jhp@...lessos.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: add
> > quirk to disable pci caps on HP Pavilion 14-ce0xxx"), but disables its
> > PCI ASPM capability of RTL8821CE directly, instead of checking DMI.
> >
> > Buglink:https://bugzilla.kernel.org/show_bug.cgi?id=215239
> > Fixes: 1d4dcaf3db9bd ("rtw88: add quirk to disable pci caps on HP Pavilion 14-ce0xxx")
> > Signed-off-by: Jian-Hong Pan <jhp@...lessos.org>
>
> We also discuss similar thing in this thread:
> https://bugzilla.kernel.org/show_bug.cgi?id=215131
>
> 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.
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?

> If so, please help to add one quirk entry of your platform.
>
> Another thing is that "attachment 299735" is another workaround for certain
> 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
>