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Message-ID: <552b1ac6-2149-48fa-9432-49655bfbc366@rowland.harvard.edu>
Date: Sun, 25 Jun 2023 16:04:29 -0400
From: Alan Stern <stern@...land.harvard.edu>
To: Guiting Shen <aarongt.shen@...il.com>
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 v2] usb: ohci-at91: Fix the unhandle interrupt when resume
On Mon, Jun 26, 2023 at 12:15:53AM +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.
>
> According to the comment in ohci_hcd_at91_drv_suspend(), it need to reset
> when resume from suspend(MEM) to fix.
>
> Signed-off-by: Guiting Shen <aarongt.shen@...il.com>
> ---
> drivers/usb/host/ohci-at91.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
> index b9ce8d80f20b..1a0356d9ea15 100644
> --- a/drivers/usb/host/ohci-at91.c
> +++ b/drivers/usb/host/ohci-at91.c
> @@ -672,7 +672,12 @@ ohci_hcd_at91_drv_resume(struct device *dev)
> else
> at91_start_clock(ohci_at91);
>
> - ohci_resume(hcd, false);
> + /*
> + * need to reset according to the comment of suspend routine,
> + * otherwise the ohci_irq would skip the interrupt if ohci_state
> + * was OHCI_RH_HALTED.
> + */
> + ohci_resume(hcd, !ohci_at91->wakeup);
This comment doesn't say why the code uses !ohci_at91->wakeup. It
should explain that. For example:
/*
* According to the comment in ohci_hcd_at91_drv_suspend()
* we need to do a reset if the 48-MHz clock was stopped,
* that is, if ohci_at91->wakeup is clear. Tell ohci_resume()
* to reset in this case by setting its "hibernated" flag.
*/
Alan Stern
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