From patchwork Mon Sep 23 19:02:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gustavo Sousa X-Patchwork-Id: 13809944 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id ADD84CF9C72 for ; Mon, 23 Sep 2024 19:03:48 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4BDA010E476; Mon, 23 Sep 2024 19:03:48 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="S/lueZAR"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) by gabe.freedesktop.org (Postfix) with ESMTPS id DD8EB10E475 for ; Mon, 23 Sep 2024 19:03:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1727118221; x=1758654221; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=XIavS8mSNwKkkWWa7VjIMR5PQYHvb/8tRg+UqJ+n5q4=; b=S/lueZARwSqv0ofrgzT4l522YL9g2O8UK5FWxpWIQIiMhoMyDv3svZLR U2GkUIcmNXNteb/Ej28EsrGJFY5Mk0BjNGpqNhPf+eTDeTNGrinZABIjn 1KbkNrsigK8+8SUCmKRzBwHXgXFnpwhbEOk+qQw+J8BKmkSX60ATP1dxR tkRzYkRD1qZ+cQCbrx9TaxZ57meS6cXR/+4KQr1g7Ja3ktNMbj7ZFMlYg IxXDfh9SVaYLzD2H66u/V0I26Xtw4rJlO0pxAwYV/2Nz0AYAegBtjzJ+A AIfGdBUN0fvARbdrQ0EllF+H24Mbg/HVGrhvHwKk3ULBmiKBLmSF0toVq w==; X-CSE-ConnectionGUID: 2TVnPL7OR3uVdNnlxKASdg== X-CSE-MsgGUID: Ojq0dCtoQByxe70WSM3H8w== X-IronPort-AV: E=McAfee;i="6700,10204,11204"; a="43601324" X-IronPort-AV: E=Sophos;i="6.10,252,1719903600"; d="scan'208";a="43601324" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2024 12:03:40 -0700 X-CSE-ConnectionGUID: J1LsSC/vQWaGz7A4VOSNYQ== X-CSE-MsgGUID: IZ/TIQkYQoqttREFChZZOQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,252,1719903600"; d="scan'208";a="71997402" Received: from bmurrell-mobl.amr.corp.intel.com (HELO gjsousa-mobl2.intel.com) ([10.125.110.180]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2024 12:03:40 -0700 From: Gustavo Sousa To: intel-gfx@lists.freedesktop.org Cc: Matt Roper Subject: [PATCH v2 4/5] drm/i915/display: Do not use ids from enum pipe in TP_printk() Date: Mon, 23 Sep 2024 16:02:53 -0300 Message-ID: <20240923190324.83013-5-gustavo.sousa@intel.com> X-Mailer: git-send-email 2.46.1 In-Reply-To: <20240923190324.83013-1-gustavo.sousa@intel.com> References: <20240923190324.83013-1-gustavo.sousa@intel.com> MIME-Version: 1.0 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Because much of kernel tracepoints is implemented at the C preprocessor level, C identifiers used in TP_printk() are saved verbatim in the event format, even when they represent compile-time constant values. As an example, we can look at the format for the intel_pipe_enable event: # cat /sys/kernel/debug/tracing/events/i915/intel_pipe_enable/format | grep '^print fmt' print fmt: "dev %s, pipe %c enable, pipe A: frame=%u, scanline=%u, pipe B: frame=%u, scanline=%u, pipe C: frame=%u, scanline=%u", __get_str(dev), REC->pipe_name, REC->frame[PIPE_A], REC->scanline[PIPE_A], REC->frame[PIPE_B], REC->scanline[PIPE_B], REC->frame[PIPE_C], REC->scanline[PIPE_C] We see that PIPE_A, PIPE_B and PIPE_C are pasted directly in the format. Because tools that interact with kernel tracepoints don't know about those ids, they'll endup failing to parse the format or produce corrupted output. For example, we can see below that trace-cmd repeats PIPE_A's frame/scanline counts for all pipes (probably because it evaluates unknown ids as zero): $ trace-cmd report -F intel_pipe_enable | tail -n5 testdisplay-8616 [000] 22048.276758: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=861, scanline=480, pipe B: frame=861, scanline=480, pipe C: frame=861, scanline=480 testdisplay-8616 [001] 22048.490287: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=867, scanline=480, pipe B: frame=867, scanline=480, pipe C: frame=867, scanline=480 testdisplay-8616 [003] 22048.700181: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=872, scanline=400, pipe B: frame=872, scanline=400, pipe C: frame=872, scanline=400 testdisplay-8616 [002] 22049.054220: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=881, scanline=2170, pipe B: frame=881, scanline=2170, pipe C: frame=881, scanline=2170 testdisplay-8616 [002] 22049.166851: intel_pipe_enable: dev 0000:00:02.0, pipe B enable, pipe A: frame=887, scanline=1632, pipe B: frame=887, scanline=1632, pipe C: frame=887, scanline=1632 , while in fact we have different values for each pipe, which can be confirmed with the raw view of the events: $ trace-cmd report -R -F intel_pipe_enable | tail -n5 testdisplay-8616 [000] 22048.276758: intel_pipe_enable: dev=0000:00:02.0 frame=ARRAY[5d, 03, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] scanline=ARRAY[e0, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe_name=A testdisplay-8616 [001] 22048.490287: intel_pipe_enable: dev=0000:00:02.0 frame=ARRAY[63, 03, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] scanline=ARRAY[e0, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe_name=A testdisplay-8616 [003] 22048.700181: intel_pipe_enable: dev=0000:00:02.0 frame=ARRAY[68, 03, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] scanline=ARRAY[90, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe_name=A testdisplay-8616 [002] 22049.054220: intel_pipe_enable: dev=0000:00:02.0 frame=ARRAY[71, 03, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] scanline=ARRAY[7a, 08, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe_name=A testdisplay-8616 [002] 22049.166851: intel_pipe_enable: dev=0000:00:02.0 frame=ARRAY[77, 03, 00, 00, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] scanline=ARRAY[60, 06, 00, 00, 39, 04, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00] pipe_name=B To fix that, we need a fix that looks more like a hack: use macros that result to integer constants instead of enum pipe values. This fixes the issue, but could break if, for whatever unlikely reason, the underlying values in the enum are changed. In the future, we should find a better way to handle this, but for now, the hack took care of the job: $ trace-cmd report -F intel_pipe_enable | tail -n5 testdisplay-9224 [003] 24324.455375: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=1103, scanline=480, pipe B: frame=0, scanline=0, pipe C: frame=0, scanline=0 testdisplay-9224 [002] 24324.669845: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=1109, scanline=480, pipe B: frame=0, scanline=0, pipe C: frame=0, scanline=0 testdisplay-9224 [003] 24324.900105: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=1115, scanline=31, pipe B: frame=0, scanline=0, pipe C: frame=0, scanline=0 testdisplay-9224 [002] 24325.256408: intel_pipe_enable: dev 0000:00:02.0, pipe A enable, pipe A: frame=1124, scanline=2171, pipe B: frame=0, scanline=0, pipe C: frame=0, scanline=0 testdisplay-9224 [003] 24325.380789: intel_pipe_enable: dev 0000:00:02.0, pipe B enable, pipe A: frame=1131, scanline=979, pipe B: frame=1, scanline=1082, pipe C: frame=0, scanline=0 v2: - Statically assert that PIPE_A == _TRACE_PIPE_A. (MattR) Reviewed-by: Matt Roper Signed-off-by: Gustavo Sousa --- .../drm/i915/display/intel_display_trace.h | 33 ++++++++++++++----- 1 file changed, 24 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers/gpu/drm/i915/display/intel_display_trace.h index 717c144e9a65..eec9aeddad96 100644 --- a/drivers/gpu/drm/i915/display/intel_display_trace.h +++ b/drivers/gpu/drm/i915/display/intel_display_trace.h @@ -23,6 +23,21 @@ #define __dev_name_display(display) dev_name((display)->drm->dev) #define __dev_name_kms(obj) dev_name((obj)->base.dev->dev) +/* + * Using identifiers from enum pipe in TP_printk() will confuse tools that + * parse /sys/kernel/debug/tracing/{xe,i915}//format. So we use CPP + * macros instead. + */ +#define _TRACE_PIPE_A 0 +#define _TRACE_PIPE_B 1 +#define _TRACE_PIPE_C 2 + +/* + * Paranoid sanity check that at least the enumeration starts at the + * same value as _TRACE_PIPE_A. + */ +static_assert(PIPE_A == _TRACE_PIPE_A); + TRACE_EVENT(intel_pipe_enable, TP_PROTO(struct intel_crtc *crtc), TP_ARGS(crtc), @@ -50,9 +65,9 @@ TRACE_EVENT(intel_pipe_enable, TP_printk("dev %s, pipe %c enable, pipe A: frame=%u, scanline=%u, pipe B: frame=%u, scanline=%u, pipe C: frame=%u, scanline=%u", __get_str(dev), __entry->pipe_name, - __entry->frame[PIPE_A], __entry->scanline[PIPE_A], - __entry->frame[PIPE_B], __entry->scanline[PIPE_B], - __entry->frame[PIPE_C], __entry->scanline[PIPE_C]) + __entry->frame[_TRACE_PIPE_A], __entry->scanline[_TRACE_PIPE_A], + __entry->frame[_TRACE_PIPE_B], __entry->scanline[_TRACE_PIPE_B], + __entry->frame[_TRACE_PIPE_C], __entry->scanline[_TRACE_PIPE_C]) ); TRACE_EVENT(intel_pipe_disable, @@ -83,9 +98,9 @@ TRACE_EVENT(intel_pipe_disable, TP_printk("dev %s, pipe %c disable, pipe A: frame=%u, scanline=%u, pipe B: frame=%u, scanline=%u, pipe C: frame=%u, scanline=%u", __get_str(dev), __entry->pipe_name, - __entry->frame[PIPE_A], __entry->scanline[PIPE_A], - __entry->frame[PIPE_B], __entry->scanline[PIPE_B], - __entry->frame[PIPE_C], __entry->scanline[PIPE_C]) + __entry->frame[_TRACE_PIPE_A], __entry->scanline[_TRACE_PIPE_A], + __entry->frame[_TRACE_PIPE_B], __entry->scanline[_TRACE_PIPE_B], + __entry->frame[_TRACE_PIPE_C], __entry->scanline[_TRACE_PIPE_C]) ); TRACE_EVENT(intel_crtc_flip_done, @@ -217,9 +232,9 @@ TRACE_EVENT(intel_memory_cxsr, TP_printk("dev %s, cxsr %s->%s, pipe A: frame=%u, scanline=%u, pipe B: frame=%u, scanline=%u, pipe C: frame=%u, scanline=%u", __get_str(dev), str_on_off(__entry->old), str_on_off(__entry->new), - __entry->frame[PIPE_A], __entry->scanline[PIPE_A], - __entry->frame[PIPE_B], __entry->scanline[PIPE_B], - __entry->frame[PIPE_C], __entry->scanline[PIPE_C]) + __entry->frame[_TRACE_PIPE_A], __entry->scanline[_TRACE_PIPE_A], + __entry->frame[_TRACE_PIPE_B], __entry->scanline[_TRACE_PIPE_B], + __entry->frame[_TRACE_PIPE_C], __entry->scanline[_TRACE_PIPE_C]) ); TRACE_EVENT(g4x_wm,