From mboxrd@z Thu Jan 1 00:00:00 1970 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 3E269C77B73 for ; Tue, 6 Jun 2023 12:48:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234308AbjFFMsN (ORCPT ); Tue, 6 Jun 2023 08:48:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231609AbjFFMsK (ORCPT ); Tue, 6 Jun 2023 08:48:10 -0400 Received: from mail-qt1-x82d.google.com (mail-qt1-x82d.google.com [IPv6:2607:f8b0:4864:20::82d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2921E10D9; Tue, 6 Jun 2023 05:47:45 -0700 (PDT) Received: by mail-qt1-x82d.google.com with SMTP id d75a77b69052e-3f9a6c18e45so15530691cf.3; Tue, 06 Jun 2023 05:47:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1686055599; x=1688647599; h=in-reply-to:content-disposition:mime-version:references:reply-to :message-id:subject:cc:to:from:date:sender:from:to:cc:subject:date :message-id:reply-to; bh=cKiZBq4N2uzyc1uP6K/gn6kRYmbs2MnPBrOh0qNFFjQ=; b=k/3CYpTYDMXNGlJOl6Vm9Siv7kMMxDjZlTRcNkC2QhX+jqbIUlq3IOMsj2Gm9A1mzc 1dYq4Re0QPPi3GaghqNM5WaUCBHiu6jq76O0VoKd/IYxcZPXxT2Z4OKVR9b8WkkF+giQ jKYV63OJOzqTaGTYSrNrTQLBooeIQQgSERqIpmX8FFG0qAMTCSgsojNChDdxd5qj4dqF 9GK9LctSx5UKPqV/E/ssgNqEmo9sp28Bo9AHbxV1iHXrpTIIVkxVGPc1jaKuzyflH86w ubo+Y7RhC7zmpeFfhjOgy/XgmvUHi6i4vNUnWpVh0me0mL4bR+Ex9WuS5Wu+Q5LTXMR3 J0jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686055599; x=1688647599; h=in-reply-to:content-disposition:mime-version:references:reply-to :message-id:subject:cc:to:from:date:sender:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=cKiZBq4N2uzyc1uP6K/gn6kRYmbs2MnPBrOh0qNFFjQ=; b=TYP4j4IRdSDQvAXRf3M/mzmTKZluBhCWTb4fr9BoABaUGA2OBJMW3JEYkoFCbk4fUE vOCuRienwmT/N4RWZZcKjqqzU4oUBem7n05vQ6qHD/PU8jyJqEIl219Zk2a1gROMzxxU Nd9tgn1G9n+xDaS70o5wIX/4WXpigHIxj4Ns7v37ejUWQn9NTzNg22mk2AxeBR4UZ9ym UcOhJCVWkR8epRYj6Ln3f1SDFt+j9uTVZdzhraO6M5+yOZSICAJ4M9V5BpZ150htYOeI p8Vdw18NIDX5n7eidsMITIoUgSO2rP+U2EA5Jjlag6KcMnHL3Gg+Ct7keVMuVZH2lzuR kN3w== X-Gm-Message-State: AC+VfDzdGq7ir+f6pIOsiX6xnZkV+fpCLlevxrkqwiYb2R6sOGJakrff HNqeiNxoOgvQ3qdESIQ5KA== X-Google-Smtp-Source: ACHHUZ7MMeHe7IIxBi59pp1HzL7wP2kz34CP+OK4jBeZLb+ItXcgXkd8wFtMZv+gD+NNBPr5K8lLeg== X-Received: by 2002:ac8:7d8e:0:b0:3f5:3d3d:d1b5 with SMTP id c14-20020ac87d8e000000b003f53d3dd1b5mr1553621qtd.27.1686055599534; Tue, 06 Jun 2023 05:46:39 -0700 (PDT) Received: from serve.minyard.net ([47.189.94.26]) by smtp.gmail.com with ESMTPSA id g22-20020ac84696000000b003ef189ffa82sm2605273qto.90.2023.06.06.05.46.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jun 2023 05:46:38 -0700 (PDT) Sender: Corey Minyard Received: from mail.minyard.net (unknown [IPv6:2001:470:b8f6:1b:6303:b09c:2f6b:4f53]) by serve.minyard.net (Postfix) with ESMTPSA id 4F393180044; Tue, 6 Jun 2023 12:46:37 +0000 (UTC) Date: Tue, 6 Jun 2023 07:46:36 -0500 From: Corey Minyard To: Johan Hovold Cc: Oliver Neukum , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/3] USB: serial: return errors from break handling Message-ID: Reply-To: minyard@acm.org References: <20230604123505.4661-1-johan@kernel.org> <726a6f5f-5338-50a9-3081-7c02194dd7af@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 06, 2023 at 01:39:03PM +0200, Johan Hovold wrote: > On Tue, Jun 06, 2023 at 01:18:19PM +0200, Oliver Neukum wrote: > > On 04.06.23 14:35, Johan Hovold wrote: > > > This series starts returning errors from break handling and also uses > > > that mechanism to report to user space when break signalling is not > > > supported (e.g. when device or driver support is missing). > > > do you eventually want this to be done for all serial devices? > > That is does cdc-acm need something like this patch? > > Looks good to me. If this turns out to confuse userspace we may have to > turn that -ENOTTY into 0 in the tty layer, but we can still use it to > avoid the unnecessary wait to "disable" the break state. > > > From 16430d9f109f904b2bfbac6e43a939209b6c4bc7 Mon Sep 17 00:00:00 2001 > > From: Oliver Neukum > > Date: Tue, 6 Jun 2023 12:57:00 +0200 > > Subject: [PATCH] usb: cdc-acm: return correct error code on unsupported break > > > > Return -ENOTTY if the device says that it doesn't support break > > so that the upper layers get error reporting right. Yeah, when I asked for this, I didn't realize that no devices did this, I thought it was a one-off with this device. There is a distinct possibility that this will break userland. This sounds like a good plan. -corey > > > > Signed-off-by: Oliver Neukum > > Acked-by: Johan Hovold > > > --- > > drivers/usb/class/cdc-acm.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c > > index 11da5fb284d0..7751f5728716 100644 > > --- a/drivers/usb/class/cdc-acm.c > > +++ b/drivers/usb/class/cdc-acm.c > > @@ -892,6 +892,9 @@ static int acm_tty_break_ctl(struct tty_struct *tty, int state) > > struct acm *acm = tty->driver_data; > > int retval; > > > > + if (!(acm->ctrl_caps & USB_CDC_CAP_BRK)) > > + return -ENOTTY; > > + > > retval = acm_send_break(acm, state ? 0xffff : 0); > > if (retval < 0) > > dev_dbg(&acm->control->dev,