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Subject: Re: [PATCH v6] xhci: re-initialize the HC during resume if HCE was
 set
To:     Puma Hsu <pumahsu@google.com>
Cc:     mathias.nyman@intel.com, Greg KH <gregkh@linuxfoundation.org>,
        Sergey Shtylyov <s.shtylyov@omp.ru>,
        Albert Wang <albertccwang@google.com>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
References: <20220129093036.488231-1-pumahsu@google.com>
 <413ce7e5-1c35-c3d0-a89e-a3c7f03b4db7@linux.intel.com>
 <CAGCq0La83AKrdk4w2b6wJLZVB0oKB7_AH3iqc4R0K1vDnqrX9A@mail.gmail.com>
From:   Mathias Nyman <mathias.nyman@linux.intel.com>
Message-ID: <86bd1bef-2f07-8dee-a125-be208903204e@linux.intel.com>
Date:   Thu, 10 Feb 2022 13:09:47 +0200
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On 8.2.2022 9.11, Puma Hsu wrote:
> On Thu, Feb 3, 2022 at 3:11 AM Mathias Nyman
> <mathias.nyman@linux.intel.com> wrote:
>>
>> On 29.1.2022 11.30, Puma Hsu wrote:
>>> When HCE(Host Controller Error) is set, it means an internal
>>> error condition has been detected. Software needs to re-initialize
>>> the HC, so add this check in xhci resume.
>>>
>>> Cc: stable@vger.kernel.org
>>> Signed-off-by: Puma Hsu <pumahsu@google.com>
>>> ---
>>> v2: Follow Sergey Shtylyov <s.shtylyov@omp.ru>'s comment.
>>> v3: Add stable@vger.kernel.org for stable release.
>>> v4: Refine the commit message.
>>> v5: Add a debug log. Follow Mathias Nyman <mathias.nyman@linux.intel.com>'s comment.
>>> v6: Fix the missing declaration for str.
>>>
>>>  drivers/usb/host/xhci.c | 7 +++++--
>>>  1 file changed, 5 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>>> index dc357cabb265..6f1198068004 100644
>>> --- a/drivers/usb/host/xhci.c
>>> +++ b/drivers/usb/host/xhci.c
>>> @@ -1091,6 +1091,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
>>>       int                     retval = 0;
>>>       bool                    comp_timer_running = false;
>>>       bool                    pending_portevent = false;
>>> +     char                    str[XHCI_MSG_MAX];
>>>
>>>       if (!hcd->state)
>>>               return 0;
>>> @@ -1146,8 +1147,10 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
>>>               temp = readl(&xhci->op_regs->status);
>>>       }
>>>
>>> -     /* If restore operation fails, re-initialize the HC during resume */
>>> -     if ((temp & STS_SRE) || hibernated) {
>>> +     /* If restore operation fails or HC error is detected, re-initialize the HC during resume */
>>> +     if ((temp & (STS_SRE | STS_HCE)) || hibernated) {
>>> +             xhci_warn(xhci, "re-initialize HC during resume, USBSTS:%s\n",
>>> +                       xhci_decode_usbsts(str, temp));
>>>
>>>               if ((xhci->quirks & XHCI_COMP_MODE_QUIRK) &&
>>>                               !(xhci_all_ports_seen_u0(xhci))) {
>>>
>>
>> Ended up modifying this patch a bit more than I first intended,
>> - don't print warning in hibernation case, only error.
>> - maybe using a lot of stack for a debug string isn't really needed.
>> - make sure we read the usbsts register before checking for the HCE bit.
>>
>> Does the below work for you? If yes, and you agree I'll apply it instead
> 
> Hi Mathias,
> Yes, your patch works for me, thanks!
> Will you submit a new patch? or should I update to a new version?
> Thanks.

I'll submit it

Thanks
-Mathias