From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51BCF29291F; Tue, 17 Jun 2025 08:22:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750148547; cv=none; b=ljBb0qXUhzaFTnTh/buaUU7xkwwc1kPL9EAS2b73gO2jBUtswpHN39nOVbzI11Z7y6GKDuxoRLVfI8Wfyd1TCeIA6jyOc+xmvO7BRaDInnOGXTGy9DSySpS0Emf26GPCVhSzXa+AjsXcAa6mo+Sg3F2tCfdbcGdh7JudLpN7o0Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750148547; c=relaxed/simple; bh=qSD98g38tfcqcNCNqmqDfpdR9ZKGR5FnULZGNDZzSp8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CILSxTzkt8BlBDmGUAjU6UqL3i7kJA3FlItl6IWvM6K+sbOpNaEnrzoSPV25Ahj28Zn9k0cAUIE8Ciw6+Z5HzQF5AEE77URBIeJtkFDs87KOBs0YMMWLfIgAcLvENVQ+vj765QR/699v7AFPAonrhD7q+pe1XCRYrSWhrTOSsz4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NVtHKPLt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NVtHKPLt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05675C4CEE3; Tue, 17 Jun 2025 08:22:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750148547; bh=qSD98g38tfcqcNCNqmqDfpdR9ZKGR5FnULZGNDZzSp8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NVtHKPLtDFARxy9PIPnoeZW5wpBnGa3PiJ62RBv23mbHM6FKjB1DTP0jfzDqrpoPm oonC6wXoLHmumULQ7TXmd2+CqswPmZBOWjKlkZ9aHc093/1GXsS10Fr4E29dVM8l6E kyVCGsIG3c/9obBoNpn0KRqHmdibITsV8qKTjJqj5DbvKrDJRqTRmAT9AHDCUpeewj 6z6ZyOycxbmoZZb2GdmaZZmUylpGNx3ORLLQqMc1kk5hFYoUEE0/f19rRNNNbzGYJ0 hqE0nfv8v/vMni9dsu7npXBtQ5UcqsYFdl1x1u62Yu2Xunqkc7YXIlgXLM05q9Wtrj U5lR/uNi31e0w== Date: Tue, 17 Jun 2025 16:22:20 +0800 From: "Peter Chen (CIX)" To: Xu Yang Cc: gregkh@linuxfoundation.org, shawnguo@kernel.org, john.ernberg@actia.se, jun.li@nxp.com, linux-usb@vger.kernel.org, imx@lists.linux.dev Subject: Re: [PATCH] usb: chipidea: udc: disconnect/reconnect from host when do suspend/resume Message-ID: <20250617082220.GB1716298@nchen-desktop> References: <20250614124914.207540-1-xu.yang_2@nxp.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250614124914.207540-1-xu.yang_2@nxp.com> On 25-06-14 20:49:14, Xu Yang wrote: > Shawn and John reported a hang issue during system suspend as below: > > - USB gadget is enabled as Ethernet > - There is data transfer over USB Ethernet (scp a big file between host > and device) > - Device is going in/out suspend (echo mem > /sys/power/state) > > The root cause is the USB device controller is suspended but the USB bus > is still active which caused the USB host continues to transfer data with > device and the device continues to queue USB requests (in this case, a > delayed TCP ACK packet trigger the issue) after controller is suspended, > however the USB controller clock is already gated off. Then if udc driver > access registers after that point, the system will hang. > > The correct way to avoid such issue is to disconnect device from host when > the USB bus is not at suspend state. Then the host will receive disconnect > event and stop data transfer in time. To continue make USB gadget device > work after system resume, this will reconnect device automatically. > > To make usb wakeup work if USB bus is already at suspend state, this will > keep connection for it only when USB device controller has enabled wakeup > capability. > > Reported-by: Shawn Guo > Reported-by: John Ernberg > Closes: https://lore.kernel.org/linux-usb/aEZxmlHmjeWcXiF3@dragon/ > Tested-by: John Ernberg # iMX8QXP > Fixes: 235ffc17d014 ("usb: chipidea: udc: add suspend/resume support for device controller") > Cc: stable@vger.kernel.org > Reviewed-by: Jun Li > Signed-off-by: Xu Yang > --- > drivers/usb/chipidea/udc.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c > index 8a9b31fd5c89..1a48e6440e6c 100644 > --- a/drivers/usb/chipidea/udc.c > +++ b/drivers/usb/chipidea/udc.c > @@ -2374,6 +2374,10 @@ static void udc_suspend(struct ci_hdrc *ci) > */ > if (hw_read(ci, OP_ENDPTLISTADDR, ~0) == 0) > hw_write(ci, OP_ENDPTLISTADDR, ~0, ~0); > + > + if (ci->gadget.connected && > + (!ci->suspended || !device_may_wakeup(ci->dev))) > + usb_gadget_disconnect(&ci->gadget); > } Don't we need to notify gadget(class) side the disconnect event? Peter > > static void udc_resume(struct ci_hdrc *ci, bool power_lost) > @@ -2384,6 +2388,9 @@ static void udc_resume(struct ci_hdrc *ci, bool power_lost) > OTGSC_BSVIS | OTGSC_BSVIE); > if (ci->vbus_active) > usb_gadget_vbus_disconnect(&ci->gadget); > + } else if (ci->vbus_active && ci->driver && > + !ci->gadget.connected) { > + usb_gadget_connect(&ci->gadget); > } > > /* Restore value 0 if it was set for power lost check */ > -- > 2.34.1 > -- Best regards, Peter