linux-kernel - Re: [PATCH] usb: host: ehci: workaround PME bug on AMD EHCI controller

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Message-ID: <CAAd53p46piFcy+JKFi6auBLON-4tPHTAHBO_DOyZyL+xxCa4PA@mail.gmail.com>
Date:   Fri, 16 Jun 2017 11:07:42 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Alan Stern <stern@...land.harvard.edu>
Cc:     Bjorn Helgaas <helgaas@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        gregkh@...uxfoundation.org, USB list <linux-usb@...r.kernel.org>,
        linux-pci@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH] usb: host: ehci: workaround PME bug on AMD EHCI controller

On Thu, Jun 15, 2017 at 10:12 PM, Alan Stern <stern@...land.harvard.edu> wrote:
> On Thu, 15 Jun 2017, Kai-Heng Feng wrote:
>
>> On Wed, Jun 14, 2017 at 1:28 AM, Bjorn Helgaas <helgaas@...nel.org> wrote:
>> >
>> > The lspci output [1] shows:
>> >
>> >   00:12.0 USB controller: Advanced Micro Devices, Inc. [AMD] FCH USB EHCI Controller (rev 39) (prog-if 20 [EHCI])
>> >     Capabilities: [c0] Power Management version 2
>> >       Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
>> >       Status: D3 NoSoftRst- PME-Enable+ DSel=0 DScale=0 PME-
>> >       Bridge: PM- B3+
>> >
>> > The device claims it can assert PME# from D3hot.  If it can't, that
>> > sounds like a hardware defect that should be addressed with a quirk.
>> > Ideally we would also have a pointer to the AMD hardware erratum.
>>
>> Looks like it's pretty similar to "23 USB Wake on Connect/Disconnect
>> with Low Speed Devices" in [1].
>> It points to a workaround in appendix A2 from [2].
>> However it says this bug only effects Low Speed devices, but it
>> actually also happens on High Speed devices.
>>
>> [1] https://support.amd.com/TechDocs/46837.pdf
>> [2] https://support.amd.com/TechDocs/42413.pdf
>
> Those documents refer to a hardware bug with a workaround in the BIOS.
> Have you checked to see if your BIOS is up to date?

Yes, it's up to date.

>
> Alan Stern
>