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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2F6EC33CB1 for ; Wed, 15 Jan 2020 10:37:30 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7F4B7222C3 for ; Wed, 15 Jan 2020 10:37:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F4B7222C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4C5FC6E903; Wed, 15 Jan 2020 10:37:29 +0000 (UTC) Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1B4C36E903 for ; Wed, 15 Jan 2020 10:37:26 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 19886193-1500050 for multiple; Wed, 15 Jan 2020 10:36:38 +0000 MIME-Version: 1.0 To: Sean Paul , dri-devel@lists.freedesktop.org From: Chris Wilson In-Reply-To: <20200114172155.215463-1-sean@poorly.run> References: <20200114172155.215463-1-sean@poorly.run> Message-ID: <157908459623.12549.3531242692320169983@skylake-alporthouse-com> User-Agent: alot/0.6 Subject: Re: [PATCH v4] drm/trace: Buffer DRM logs in a ringbuffer accessible via debugfs Date: Wed, 15 Jan 2020 10:36:36 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-doc@vger.kernel.org, David Airlie , Daniel Vetter , Jonathan Corbet , Steven Rostedt , Sean Paul , Thomas Zimmermann Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Quoting Sean Paul (2020-01-14 17:21:43) > From: Sean Paul > > This patch uses a ring_buffer to keep a "flight recorder" (name credit Weston) > of DRM logs for a specified set of debug categories. The user writes a > bitmask of debug categories to the "trace_mask" node and can read log > messages from the "trace" node. > > These nodes currently exist in debugfs under the dri directory. I > intended on exposing all of this through tracefs originally, but the > tracefs entry points are not exposed, so there's no way to create > tracefs files from drivers at the moment. I think it would be a > worthwhile endeavour, but one requiring more time and conversation to > ensure the drm traces fit somewhere sensible. Fwiw, I have a need for client orientated debug message store, with the primary purpose of figuring out -EINVAL. We need per-client so we can put sensitive information about the potentially buggy client behaviour, and of course it needs to be accessible by the non-privileged client. On the execution side, it's easy to keep track of the client so we could trace execution flow per client, within reason. And we could do similarly for kms clients. Just chiming to say, I don't think a duplicate of dmesg hidden inside debugfs achieves much. But a generic tracek-esque ringbuf would be very useful -- even if only so we can separate our GEM_TRACE from the global tracek. -Chris _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel