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Subject: Re: [PATCH] xhci: Prevent runtime suspend all the time with
 XHCI_RESET_ON_RESUME quirk
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Oliver Neukum <oneukum@suse.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "open list:USB XHCI DRIVER" <linux-usb@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20200504091952.15820-1-kai.heng.feng@canonical.com>
 <1588585655.13662.5.camel@suse.com>
 <88A0FF32-C7D7-4E49-8470-FE23401371BD@canonical.com>
From:   Mathias Nyman <mathias.nyman@intel.com>
Message-ID: <6fca4532-b4a2-9730-bd96-5ac15357f752@intel.com>
Date:   Mon, 4 May 2020 13:13:02 +0300
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On 4.5.2020 13.02, Kai-Heng Feng wrote:
> 
> 
>> On May 4, 2020, at 17:47, Oliver Neukum <oneukum@suse.com> wrote:
>>
>> Am Montag, den 04.05.2020, 17:19 +0800 schrieb Kai-Heng Feng:
>>> Etron EJ168 USB 3.0 Host Controller stops working after S3, if it was
>>> runtime suspended previously:
>>> [  370.080359] pci 0000:02:00.0: can't change power state from D3cold to D0 (config space inaccessible)
>>
>> Apparently this controller has issues with D3cold
>>
>>> [  370.080477] xhci_hcd 0000:04:00.0: can't change power state from D3cold to D0 (config space inaccessible)
>>> [  370.080532] pcieport 0000:00:1c.0: DPC: containment event, status:0x1f05 source:0x0200
>>> [  370.080533] pcieport 0000:00:1c.0: DPC: ERR_FATAL detected
>>> [  370.080536] xhci_hcd 0000:04:00.0: can't change power state from D3hot to D0 (config space inaccessible)
>>> [  370.080552] xhci_hcd 0000:04:00.0: AER: can't recover (no error_detected callback)
>>> [  370.080566] usb usb3: root hub lost power or was reset
>>> [  370.080566] usb usb4: root hub lost power or was reset
>>> [  370.080572] xhci_hcd 0000:04:00.0: Host halt failed, -19
>>> [  370.080574] xhci_hcd 0000:04:00.0: Host not accessible, reset failed.
>>> [  370.080575] xhci_hcd 0000:04:00.0: PCI post-resume error -19!
>>> [  370.080586] xhci_hcd 0000:04:00.0: HC died; cleaning up
>>>
>>> This can be fixed by not runtime suspend the controller at all.
>>>
>>> So instead of conditionally runtime suspend the controller, always
>>> prevent runtime suspend with XHCI_RESET_ON_RESUME quirk.
>>
>> What does that do to other controllers that can do runtime suspend
>> under the current scheme?
> 
> Ok, I'll add a new quirk specific to this controller.
> 
> Kai-Heng

Host shouldn't runtime suspend by default unless set by userspace, or
it has XHCI_DEFAULT_PM_RUNTIME_ALLOW quirk set.  

-Mathias