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

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Date:   Mon, 13 Dec 2021 08:59:55 +0000
From:   Pkshih <pkshih@...ltek.com>
To:     Jian-Hong Pan <jhp@...lessos.org>
CC:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        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


> -----Original Message-----
> From: Jian-Hong Pan <jhp@...lessos.org>
> Sent: Monday, December 13, 2021 3:31 PM
> To: Pkshih <pkshih@...ltek.com>
> Cc: Kai-Heng Feng <kai.heng.feng@...onical.com>; Yan-Hsuan Chuang <tony0620emma@...il.com>; Kalle Valo
> <kvalo@...eaurora.org>; linux-wireless@...r.kernel.org; netdev@...r.kernel.org;
> linux-kernel@...r.kernel.org; linux@...lessos.org
> Subject: Re: [PATCH] rtw88: 8821c: disable the ASPM of RTL8821CE
> 
> Pkshih <pkshih@...ltek.com> 於 2021年12月11日 週六 下午2:31寫道：
> >
> >
> > > -----Original Message-----
> > > From: Jian-Hong Pan <jhp@...lessos.org>
> > > Sent: Friday, December 10, 2021 5:34 PM
> > > To: Kai-Heng Feng <kai.heng.feng@...onical.com>
> > > Cc: Pkshih <pkshih@...ltek.com>; Yan-Hsuan Chuang <tony0620emma@...il.com>; Kalle Valo
> > > <kvalo@...eaurora.org>; linux-wireless@...r.kernel.org; netdev@...r.kernel.org;
> > > linux-kernel@...r.kernel.org; linux@...lessos.org
> > > Subject: Re: [PATCH] rtw88: 8821c: disable the ASPM of RTL8821CE
> > >
> > > Kai-Heng Feng <kai.heng.feng@...onical.com> 於 2021年12月10日 週五 下午5:24寫道：
> > >
> > > > 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, could you try Kai-Heng's workaround that only turn off ASPM
> > during NAPI poll function. If it also works to you, I think it is okay
> > to apply this workaround to all Intel platform with RTL8821CE chipset.
> > Because this workaround has little (almost no) impact of power consumption.
> 
> According to Kai-Heng's hack patch [1] and the comment [2] mentioning
> checking "ref_cnt" by rtw_pci_link_ps(), I arrange the patch as
> following.

I meant that move "ref_cnt" into rtw_pci_link_ps() by [2], but you remove
the "ref_cnt". This leads lower performance, because it must turn off
ASPM after napi_poll() when we have high traffic.

In fact, Kai-Heng's patch is to leave ASPM before napi_poll(), and
"restore" ASPM setting. So, we still need "ref_cnt".


> This patch only disables ASPM (if the hardware has the capability)
> when system gets into rtw_pci_napi_poll() and re-enables ASPM when it
> leaves rtw_pci_napi_poll().  It is as Ping-Ke mentioned "only turn off
> ASPM during NAPI poll function".
> The WiFi & BT work, and system is still alive after I use the internet
> awhile.  Besides, there is no more "pci bus timeout, check dma status"
> error.
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=215131#c11
> [2] https://bugzilla.kernel.org/show_bug.cgi?id=215131#c15
> 
> Jian-Hong Pan
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/pci.c
> b/drivers/net/wireless/realtek/rtw88/pci.c
> index a7a6ebfaa203..a6fdddecd37d 100644
> --- a/drivers/net/wireless/realtek/rtw88/pci.c
> +++ b/drivers/net/wireless/realtek/rtw88/pci.c
> @@ -1658,6 +1658,7 @@ static int rtw_pci_napi_poll(struct napi_struct
> *napi, int budget)
>                                               priv);
>         int work_done = 0;
> 
> +       rtw_pci_link_ps(rtwdev, false);
>         while (work_done < budget) {
>                 u32 work_done_once;
> 
> @@ -1681,6 +1682,7 @@ static int rtw_pci_napi_poll(struct napi_struct
> *napi, int budget)
>                 if (rtw_pci_get_hw_rx_ring_nr(rtwdev, rtwpci))
>                         napi_schedule(napi);
>         }
> +       rtw_pci_link_ps(rtwdev, true);
> 
>         return work_done;
>  }
> 

How about doing this thing only if 8821CE and Intel platform?
Could you help to add this?

--
Ping-ke