Re: [PATCH] usb: dwc3: Fix the USB 3.0 hub detection bug after warm boot

[Felipe Balbi]

Hi,

gustavo panizzo <gfa@xxxxxxxxxxxx> writes:
>>> On Wed, Jul 12, 2017 at 02:08:04PM +0800, Baolin Wang wrote:
>>>>
>>>> Hi,
>>>>
>>>> On 12 July 2017 at 11:52, gustavo panizzo <gfa@xxxxxxxxxxxx> wrote:
>>>>>
>>>>> The dwc3 could not release resources when the module is built-in
>>>>> because this module does not have shutdown method. This causes the USB
>>>>> 3.0 hub is not able to detect after warm boot.
>>>>>
>>>>> Original patch by Brian Kim, updated and submitted upstream by gustavo
>>>>> panizzo.
>>>>>
>>>>> Also see https://bugs.debian.org/843448
>>>>>
>>>>> Signed-off-by: Brian Kim <brian.kim@xxxxxxxxxxxxxx>
>>>>> Signed-off-by: gustavo panizzo <gfa@xxxxxxxxxxxx>
>>>>> ---
>>>>>  drivers/usb/dwc3/core.c | 33 +++++++++++++++++++++++++++++++++
>>>>>  1 file changed, 33 insertions(+)
>>>>>
>>>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>>>>> index 326b302fc440..f92dfe213d89 100644
>>>>> --- a/drivers/usb/dwc3/core.c
>>>>> +++ b/drivers/usb/dwc3/core.c
>>>>> @@ -1259,6 +1259,38 @@ static int dwc3_probe(struct platform_device
>>>>> *pdev)
>>>>>         return ret;
>>>>>  }
>>>>>
>>>>> +static void dwc3_shutdown(struct platform_device *pdev)
>>>>> +{
>>>>> +       struct dwc3     *dwc = platform_get_drvdata(pdev);
>>>>> +       struct resource *res = platform_get_resource(pdev,
>>>>> IORESOURCE_MEM, 0);
>>>>> +
>>>>> +       pm_runtime_get_sync(&pdev->dev);
>>>>> +       /*
>>>>> +        * restore res->start back to its original value so that, in case
>>>>> the
>>>>> +        * probe is deferred, we don't end up getting error in request
>>>>> the
>>>>> +        * memory region the next time probe is called.
>>>>> +        */
>>>>> +       res->start -= DWC3_GLOBALS_REGS_START;
>>>>> +
>>>>> +       dwc3_debugfs_exit(dwc);
>>>>> +       dwc3_core_exit_mode(dwc);
>>>>> +       dwc3_event_buffers_cleanup(dwc);
>>>
>>>
>>> What about dwc3_event_buffers_cleanup? should I remove it from
>>> dwc3_shutdown()?
>>> It is already in dwc3_core_exit()
>>
>>I think so. We should avoid duplicate code.
>>
>>>>> +       dwc3_free_event_buffers(dwc);
>>>>> +
>>>>> +       usb_phy_set_suspend(dwc->usb2_phy, 1);
>>>>> +       usb_phy_set_suspend(dwc->usb3_phy, 1);
>>>>> +
>>>>> +       phy_power_off(dwc->usb2_generic_phy);
>>>>> +       phy_power_off(dwc->usb3_generic_phy);
>>>>
>>>>
>>>> We've done these in dwc3_core_exit().
>
> This is the patch after testing on a Odroid XU4, on top of linux-next 
> 964bcc1b4f57028d56dace7d9bc5924f2eb43f36 which translates to 4.13.0-rc1-next-20170717+
> I tested this patch for a week without problems with heavy USB and NIC usage.
> Please consider merging it
>
>
> Author: gustavo panizzo <gfa@xxxxxxxxxxxx>
> Date:   Wed Jul 12 11:26:55 2017 +0800
>
>     usb: dwc3: Fix the USB 3.0 hub detection bug after warm boot
>     
>     The dwc3 could not release resources when the module is built-in
>     because this module does not have shutdown method. This causes the USB
>     3.0 hub is not able to detect after warm boot.
>     
>     Original patch by Brian Kim, updated and submitted upstream by gustavo
>     panizzo.

if the original patch is from Brian, then 'Author' should be
Brian. Please fix it.

I also don't get why all of a sudden we need to implement
->shutdown(). Why is it that we never needed it before and we need it now?

Care to bisect to find the first commit which started causing this
problem?

-- 
balbi

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