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Message-ID: <aaa64572fac0fc411b79a9adb59b5bbcbdf4b1a8.camel@ettle.org.uk>
Subject: Re: rtsx_pci not restoring ASPM state after suspend/resume
From:   James Ettle <james@ettle.org.uk>
To:     Bjorn Helgaas <helgaas@kernel.org>,
        =?UTF-8?Q?=E5=90=B3=E6=98=8A=E6=BE=84?= Ricky 
        <ricky_wu@realtek.com>
Cc:     Rui Feng <rui_feng@realsil.com.cn>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Len Brown <lenb@kernel.org>,
        Puranjay Mohan <puranjay12@gmail.com>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jacopo De Simoi <wilderkde@gmail.com>
Date:   Sat, 25 Jul 2020 21:27:11 +0100
In-Reply-To: <20200724231309.GA1551055@bjorn-Precision-5520>
References: <20200724231309.GA1551055@bjorn-Precision-5520>
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On Fri, 2020-07-24 at 18:13 -0500, Bjorn Helgaas wrote:
> 
> Maybe we should simplify this a little bit more.  James, if you don't
> touch ASPM config at all, either manually or via udev, does the ASPM
> configuration stay the same across suspend/resume?
> 

Yes, it stays the same. Explicitly: 

With the udev rule disabled, immediately following clean boot from
power-off (and no additional tinkering), ASPM is OFF to the best of my
knowledge:

 - link/l1_aspm in sysfs is 0 for PCI devices 0000:01:00.[01];
 - the processor sleeps no deeper than package C3.

The situation above is the same following a suspend/resume cycle --
both in terms of sysfs, and observed package C-state occupancy.

[Tested on kernel 5.7.10, but the behaviour is the same as prior
kernels.]

Thanks,
James.