From patchwork Wed Nov 30 12:15:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Kepplinger X-Patchwork-Id: 629846 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 750BCC352A1 for ; Wed, 30 Nov 2022 12:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234359AbiK3MQk (ORCPT ); Wed, 30 Nov 2022 07:16:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbiK3MQj (ORCPT ); Wed, 30 Nov 2022 07:16:39 -0500 Received: from comms.puri.sm (comms.puri.sm [159.203.221.185]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10AC62B600; Wed, 30 Nov 2022 04:16:38 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by comms.puri.sm (Postfix) with ESMTP id B84EDF5D85; Wed, 30 Nov 2022 04:16:07 -0800 (PST) Received: from comms.puri.sm ([127.0.0.1]) by localhost (comms.puri.sm [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Nl2cF25mKZO5; Wed, 30 Nov 2022 04:16:06 -0800 (PST) From: Martin Kepplinger DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=puri.sm; s=comms; t=1669810566; bh=XfQt2gqNGwqTBmezWa2hrCNNLvlXxzmo4l3Y1L8uyqY=; h=From:To:Cc:Subject:Date:From; b=HZu8T6F6Wbj9H8NlWoGXQ2Znl+AA/k3uR+zDLGnWC4pwM9k15ignOq3mfPUoZh2f7 Z1AnTIp09I203/ELknoEAAjrBGDLKjavWU9J8ED0pbKow44NklS8xwQuSd8w30fmWa mhUZgyRJi7R7YJAEJflIEYzsLP7of46CM8eOJXs4NFKulJJEYvmm1rnExI92Av/WTt XhCp1nZrHLAv6R6iC5leDKw/KxAYdUi44n5R6MJz0mC/xRV2NKL6Z+kig2Y3iRfM2x flENVdK4aQnzAx+FXGZayZPVJzXacRzYDt/CJv4NEkZ5LyZur2kVNq0F6bo+yNf/K/ cPyveGWxpy3TA== To: johan@kernel.org, gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, phone-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Kepplinger Subject: [RFC v1] hack: suspend: usb: option: add reset_resume callback Date: Wed, 30 Nov 2022 13:15:52 +0100 Message-Id: <20221130121552.1560379-1-martin.kepplinger@puri.sm> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Currently to be the same as resume(). This will just avoid re-enumeration of the modem device on every system resume. This exists only because the usb core will re-enumerate *any* device whos' driver doesn't have reset_resume() implemented. A call trace: Jun 23 11:15:43 pureos kernel: usb_serial_disconnect+0x58/0x180 [usbserial] Jun 23 11:15:43 pureos kernel: usb_unbind_interface+0x84/0x290 [usbcore] Jun 23 11:15:43 pureos kernel: device_remove+0x78/0x90 Jun 23 11:15:43 pureos kernel: device_release_driver_internal+0x1e4/0x250 Jun 23 11:15:43 pureos kernel: device_release_driver+0x24/0x30 Jun 23 11:15:43 pureos kernel: usb_forced_unbind_intf+0xac/0xd4 [usbcore] Jun 23 11:15:43 pureos kernel: unbind_marked_interfaces.isra.0+0x5c/0x80 [usbcore] Jun 23 11:15:43 pureos kernel: usb_resume+0x78/0x8c [usbcore] Jun 23 11:15:43 pureos kernel: usb_dev_resume+0x20/0x30 [usbcore] Jun 23 11:15:43 pureos kernel: dpm_run_callback+0x60/0x1f0 Jun 23 11:15:43 pureos kernel: device_resume+0x9c/0x1f4 where usb_resume_inteface() sets needs_binding here https://elixir.bootlin.com/linux/latest/source/drivers/usb/core/driver.c#L1353 because of no reset_resume() implementation. This hack is even suggested in some modems' application notes as can be found in discussion here https://invent.kde.org/teams/plasma-mobile/issues/-/issues/3#note_218386 Signed-off-by: Martin Kepplinger --- drivers/usb/serial/option.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c index dee79c7d82d5..58526bf8684d 100644 --- a/drivers/usb/serial/option.c +++ b/drivers/usb/serial/option.c @@ -46,6 +46,7 @@ static int option_probe(struct usb_serial *serial, static int option_attach(struct usb_serial *serial); static void option_release(struct usb_serial *serial); static void option_instat_callback(struct urb *urb); +static int option_reset_resume(struct usb_serial *serial); /* Vendor and product IDs */ #define OPTION_VENDOR_ID 0x0AF0 @@ -2227,6 +2228,7 @@ static struct usb_serial_driver option_1port_device = { #ifdef CONFIG_PM .suspend = usb_wwan_suspend, .resume = usb_wwan_resume, + .reset_resume = option_reset_resume, #endif }; @@ -2373,6 +2375,18 @@ static void option_instat_callback(struct urb *urb) } } +static int option_reset_resume(struct usb_serial *serial) +{ + /* + * We simply call resume() because this implementation only + * exists because the USB core will un- and rebind any driver + * during system resume that does *not* have a reset_resume() + * implementation; see usb_resume_interface() in core/driver.c + * We want to avoid that unconditional removal/addition. + */ + return usb_wwan_resume(serial); +} + MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL v2");