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Subject: Re: [PATCH v1] rtw88: pci: disable aspm for platform inter-op with
 module parameter
To:     yhchuang@realtek.com, kvalo@codeaurora.org
Cc:     kernel@iuliancostan.com, linux-wireless@vger.kernel.org, i@outv.im,
        trevor@shartrec.com
References: <20200605074703.32726-1-yhchuang@realtek.com>
From:   Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <5def4c90-5143-68f1-201f-b0590f85dde6@lwfinger.net>
Date:   Sat, 20 Jun 2020 14:53:15 -0500
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On 6/5/20 2:47 AM, yhchuang@realtek.com wrote:
> From: Yan-Hsuan Chuang <yhchuang@realtek.com>
> 
> Some platforms cannot read the DBI register successfully for the
> ASPM settings. After the read failed, the bus could be unstable,
> and the device just became unavailable [1]. For those platforms,
> the ASPM should be disabled. But as the ASPM can help the driver
> to save the power consumption in power save mode, the ASPM is still
> needed. So, add a module parameter for them to disable it, then
> the device can still work, while others can benefit from the less
> power consumption that brings by ASPM enabled.
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=206411
> [2] Note that my lenovo T430 is the same.

As someone who maintains these drivers in a GitHub repo so that users of older 
kernels can have access to them, I am in favor of this module option. Only a 
very few cases would need to disable ASPM, and I see no reason for everyone else 
to use additional power as would be needed with automatic disabling. Adding a 
new machine to some quirk list would be more difficult than merely telling a 
novice user how to turn ASPM off for their system.

In case someone is collecting machines that would need a quirk, I found another 
one as shown in https://github.com/lwfinger/rtlwifi_new/issues/622. That one is 
a Lenovo Thinkpad E490.

Larry