linux-kernel - Re: [PATCH] usb: ohci-at91: Fix the unhandle interrupt when resume

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Message-ID: <c2d0b37a-3ee1-e07e-e265-c71895474ba8@gmail.com>
Date:   Fri, 23 Jun 2023 11:44:04 +0800
From:   Guiting Shen <aarongt.shen@...il.com>
To:     Alan Stern <stern@...land.harvard.edu>
Cc:     gregkh@...uxfoundation.org, nicolas.ferre@...rochip.com,
        alexandre.belloni@...tlin.com, claudiu.beznea@...rochip.com,
        linux-usb@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] usb: ohci-at91: Fix the unhandle interrupt when resume



On Thu,Jun 22,2023 at 22:29:43PM GMT+8, Alan Stern wrote:
> On Thu, Jun 22, 2023 at 10:57:39AM +0800, Guiting Shen wrote:
>> The ohci_hcd_at91_drv_suspend() sets ohci->rh_state to OHCI_RH_HALTED when
>> suspend which will let the ohci_irq() skip the interrupt after resume. And
>> nobody to handle this interrupt.
>>
>> Set the ohci->rh_state to OHCI_RH_SUSPEND instead of OHCI_RH_HALTED when
>> suspend to fix it.
>>
>> Signed-off-by: Guiting Shen <aarongt.shen@...il.com>
>> ---
>>   drivers/usb/host/ohci-at91.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
>> index b9ce8d80f20b..7a970e573668 100644
>> --- a/drivers/usb/host/ohci-at91.c
>> +++ b/drivers/usb/host/ohci-at91.c
>> @@ -645,7 +645,7 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
>>   	 * REVISIT: some boards will be able to turn VBUS off...
>>   	 */
>>   	if (!ohci_at91->wakeup) {
>> -		ohci->rh_state = OHCI_RH_HALTED;
>> +		ohci->rh_state = OHCI_RH_SUSPENDED;
> 
> It looks like this change ignores the comment immediately above it
> (just before the start of this hunk).
> 
> If you want to find a way to handle IRQs better after the controller
> resumes, maybe you should change the resume routine instead of the
> suspend routine.
>
> Alan Stern

The comment which was added with commit-id 0365ee0a8f745 may be outdated
because ohci_suspend() and ohci_at91_port_suspend() is used to suspend 
instead of setting ohci->rh_state to OHCI_RH_HALTED.

What's more, I found that only ohci-at91 driver to set the 
ohci->rh_state which may be unnessory because the ohci_suspend() disable 
irq emission and mark HW unaccessible and ohci_at91_port_suspend() 
suspend the controller.

Is it really need to set ohci->rh_state in ohci_hcd_at91_drv_suspend()?

It maybe confused to set ohci->rh_state to OHCI_RH_SUSPEND in resume 
routine.

-- 
Best regards,
Guiting Shen