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Subject: Re: [PATCH] xhci: print warning when HCE was set
To:     Mathias Nyman <mathias.nyman@linux.intel.com>,
        <gregkh@linuxfoundation.org>, <mathias.nyman@intel.com>
CC:     <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <yisen.zhuang@huawei.com>
References: <20220915011134.58400-1-liulongfang@huawei.com>
 <6b5a45f1-caf3-4259-77da-e36788f5b8a9@linux.intel.com>
 <2648444c-2f2a-4d9b-8545-6677663adcf0@huawei.com>
 <8271d551-4034-71fe-5be4-e08e28b6dd6b@linux.intel.com>
From:   liulongfang <liulongfang@huawei.com>
Message-ID: <19ab61d6-c2a2-42be-2bb6-500636868703@huawei.com>
Date:   Fri, 14 Oct 2022 11:12:10 +0800
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On 2022/9/26 15:58, Mathias Nyman wrote:
> On 24.9.2022 5.35, liulongfang wrote:
>> On 2022/9/22 21:01, Mathias Nyman Wrote:
>>> Hi
>>>
>>> On 15.9.2022 4.11, Longfang Liu wrote:
>>>> When HCE(Host Controller Error) is set, it means that the xhci hardware
>>>> controller has an error at this time, but the current xhci driver
>>>> software does not log this event.
>>>>
>>>> By adding an HCE event detection in the xhci interrupt processing
>>>> interface, a warning log is output to the system, which is convenient
>>>> for system device status tracking.
>>>>
>>>
>>> xHC should cease all activity when it sets HCE, and is probably not
>>> generating interrupts anymore.
>>>
>>> Would probably be more useful to check for HCE at timeouts than in the
>>> interrupt handler.
>>>
>>
>> Which function of the driver code is this timeout in?
> 
> xhci_handle_command_timeout() will usually trigger at some point,
> 

Because this HCE error is reported in the form of an interrupt signal, it is more
concise to put it in xhci_irq() than in xhci_handle_command_timeout().

>>
>>> If this is something seen on actual hardware then it makes sense to add it.
>>>
>>
>> This HCE error is sure to report an interrupt on the chip we are using.
> 
> Ok, then makes sense to add this patch.
> 
> Thanks
> -Mathias
>
Thanks,
Longfang.
> .
>