Messages in this thread | | | Date | Mon, 19 Jun 2017 12:45:33 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH] usb: host: ehci: workaround PME bug on AMD EHCI controller |
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On Mon, Jun 19, 2017 at 11:30:18AM +0800, Kai-Heng Feng wrote: > On Sat, Jun 17, 2017 at 1:30 AM, Alan Stern <stern@rowland.harvard.edu> wrote: > > On Sat, 17 Jun 2017, Kai-Heng Feng wrote: > > > >> On Fri, Jun 16, 2017 at 11:07 AM, Kai-Heng Feng > >> <kai.heng.feng@canonical.com> wrote: > >> > On Thu, Jun 15, 2017 at 10:12 PM, Alan Stern <stern@rowland.harvard.edu> wrote: > >> >> 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, I re-sent a patch but I forgot to add you to CC list: > >> http://marc.info/?l=linux-pci&m=149760607914628&w=2 > > > > Thanks for letting me know. The patch seems reasonable. > > > > Have you tested it with system suspend? That is, if you suspend the > > whole computer, does plugging or unplugging a USB device cause the > > system to wake up? > > No, the system will not wake up when plugging or unplugging. > Tried several times, nether runtime PM enabled nor runtime PM disabled > will wake up the system under S3, when (un)plugging USB devices.
Alan, I don't know what this test means for the patch (http://marc.info/?l=linux-pci&m=149760607914628&w=2).
pci_target_state() is documented as "return the deepest state from which the device can generate wake events." For this device, I guess that means D2, and the patch should accomplish that.
I don't know what's supposed to happen to this device when the system is in S3. I assume that if the system is in S3, most devices are in D3. If this device is in D3, we won't get PMEs, which I guess is what Kai-Heng is seeing. Is that the desired behavior? Or do we want the PMEs enough that we should leave the device in D2 (if that's even possible)?
Bjorn
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