From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 71359 invoked by alias); 9 Aug 2016 17:34:02 -0000 Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org Received: (qmail 71345 invoked by uid 89); 9 Aug 2016 17:34:01 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=0.1 required=5.0 tests=AWL,BAYES_50,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 spammy=blvd, alto, Blvd, replies X-HELO: homiemail-a43.g.dreamhost.com Received: from sub5.mail.dreamhost.com (HELO homiemail-a43.g.dreamhost.com) (208.113.200.129) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Tue, 09 Aug 2016 17:33:51 +0000 Received: from homiemail-a43.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a43.g.dreamhost.com (Postfix) with ESMTP id 7526C600360E for ; Tue, 9 Aug 2016 10:33:49 -0700 (PDT) Received: from vm-fedora21.eagercon.com (c-71-202-23-94.hsd1.ca.comcast.net [71.202.23.94]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: eager@eagerm.com) by homiemail-a43.g.dreamhost.com (Postfix) with ESMTPSA id 5953F600360D for ; Tue, 9 Aug 2016 10:33:49 -0700 (PDT) To: "gdb@sourceware.org" From: Michael Eager Subject: Remote Serial Protocol -- reply to '?' when target running Message-ID: <57AA13FC.2000707@eagerm.com> Date: Tue, 09 Aug 2016 17:34:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes X-SW-Source: 2016-08/txt/msg00006.txt.bz2 When gdb connects to a remote target, it asks about features, and then sends a '?' packet, asking why the target is stopped. When the target connection is through a JTAG pod, the pod may be able to respond to the feature request, but not be able to determine what the current state of the target is, likely because it is not stopped. What should a JTAG pod reply in this case? The GDB Remote Protocol doc doesn't seem to be entirely consistent. The description for '?' is Indicate the reason the target halted. The reply is the same as for step and continue. The description for Stop Reply Packet says the following: The =E2=80=98C=E2=80=99, =E2=80=98c=E2=80=99, =E2=80=98S=E2=80=99, =E2= =80=98s=E2=80=99, =E2=80=98vCont=E2=80=99, =E2=80=98vAttach=E2=80=99, =E2= =80=98vRun=E2=80=99, =E2=80=98vStopped=E2=80=99, and =E2=80=98?=E2=80=99 packets can receive any of the below as a reply.= Except for =E2=80=98?=E2=80=99 and =E2=80=98vStopped=E2=80=99, that reply is on= ly returned when the target halts. This suggests that the target can reply to '?' even if it is not stopped, which seems to contradict the description for '?'. But none of the listed replies seem to be appropriate. None of the replies look like "Don't bother me, I'm busy". How should the JTAG pod respond? What do most do in this situation? --=20 Michael Eager eager@eagercon.com 1960 Park Blvd., Palo Alto, CA 94306 650-325-8077