From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: [PATCH] Tracing events with GPIOs Date: Thu, 2 Jan 2014 13:43:40 +0100 Message-ID: References: <1387239745-2890-1-git-send-email-jjhiblot@traphandler.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Alexandre Courbot Cc: Jean-Jacques Hiblot , Steven Rostedt , masami.hiramatsu.pt@hitachi.com, "linux-gpio@vger.kernel.org" , Linux Kernel Mailing List List-Id: linux-gpio@vger.kernel.org On Thu, Dec 19, 2013 at 7:52 AM, Alexandre Courbot wrote: > On Tue, Dec 17, 2013 at 9:22 AM, Jean-Jacques Hiblot > wrote: >> >> This patch implements a new tracing mechanism based on kprobes and using GPIO. >> Debugging with GPIO is very common in the embedded world. At least for those of us >> fortunate enough to have an oscilloscope or a logic analyzer on their bench... >> This is especially true if the issue results of a hardware/sofware interaction. >> >> Typical use cases are : >> * mixed software/hardware debugging. For example when the software detects a >> situation of interest (typically an error) it toggles a GPIO to trigger the >> oscilloscope acquisition. >> * direct latency/duration measurements. >> >> examples: >> To trig the oscilloscope whenever a mmc command error: >> echo "p:my_mmc_blk_error mmc_blk_cmd_error gpiopulse@13" > /sys/kernel/debug/tracing/kprobe_events >> echo 1 > /sys/kernel/debug/tracing/events/kprobes/my_mmc_blk_error/enable I've never seen the whole patch. Can you please repost this and include linux-gpio@vger.kernel.org and also me on the To: line? Yours, Linus Walleij