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

Alan Stern
2017-06-15T14:12:18Z

On Thu, 15 Jun 2017, Kai-Heng Feng wrote:

> On Wed, Jun 14, 2017 at 1:28 AM, Bjorn Helgaas <helgaas@kernel.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?

Alan Stern