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 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 5565DD6ACF4 for ; Wed, 27 Nov 2024 17:25:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ECC8A10E146; Wed, 27 Nov 2024 17:25:04 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="cdSNEPfJ"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5E35010E110; Wed, 27 Nov 2024 17:25:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1732728303; x=1764264303; h=from:to:subject:in-reply-to:references:date:message-id: mime-version; bh=z6lYj3XqyRF01Zm5W1AiSdqHxbrxN4aA6QHY7KP2Nc4=; b=cdSNEPfJ+HdYAZl0R/LNWdrRW4obeePU/YsGx/mbE3CsNWwPJxVvNxw8 96ln211eTh4qufvi3FPGSesKKJmKy53Y7V5zB4LP6ksDcbypXaXib1HUw R95lSawvST/1pS1i7GZkVBNK4ABx3/imheWmm4hwxl3FQvuw35YQ2jcPO glbsjQMlAtfJhGzJ0Ce2vf7gIWLnJmDk2QufG4xxlJs1UE5N0ACgZ8Gth /Cr4szoDhKS4bGyn67g9pXGZzZ1BRyk0Vnjjw5guPLIXpkSbXuTqxAIkx qroOgi7EcC7Z4eikCr616CyeBCls7zy+/itq1PSblEguyIalAAEH55kGU g==; X-CSE-ConnectionGUID: A3GOPfqdRxmrBtyIpGaahw== X-CSE-MsgGUID: 3ipphpTGTsKr2GVeSzIKQQ== X-IronPort-AV: E=McAfee;i="6700,10204,11269"; a="33098466" X-IronPort-AV: E=Sophos;i="6.12,189,1728975600"; d="scan'208";a="33098466" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2024 09:25:02 -0800 X-CSE-ConnectionGUID: Mw/ye2vPQGu1Rk4BcKo3/w== X-CSE-MsgGUID: ZeiOAPNHSUSncgFe+j76SA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,189,1728975600"; d="scan'208";a="91936622" Received: from carterle-desk.ger.corp.intel.com (HELO localhost) ([10.245.246.110]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2024 09:25:01 -0800 From: Jani Nikula To: Gustavo Sousa , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Subject: Re: [PATCH] drm/i915/dp: use seq buf for printing rates In-Reply-To: <173272067132.9041.672991565423824805@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20241127131838.3268735-1-jani.nikula@intel.com> <173272067132.9041.672991565423824805@intel.com> Date: Wed, 27 Nov 2024 19:24:58 +0200 Message-ID: <87mshkwpw5.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Wed, 27 Nov 2024, Gustavo Sousa wrote: > Quoting Jani Nikula (2024-11-27 10:18:38-03:00) >>Hand rolling the buffer overflow handling with snprintf() is a bit >>tedious. The seq_buf interface is made for this. Switch to it. > > Cool! Today I learned a new kernel interface. :-) \o/ >> >>Use struct intel_display while at it. >> >>Signed-off-by: Jani Nikula >>--- >> drivers/gpu/drm/i915/display/intel_dp.c | 36 ++++++++++--------------- >> 1 file changed, 14 insertions(+), 22 deletions(-) >> >>diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c >>index 053a9a4182e7..4471c8fcd478 100644 >>--- a/drivers/gpu/drm/i915/display/intel_dp.c >>+++ b/drivers/gpu/drm/i915/display/intel_dp.c >>@@ -28,6 +28,7 @@ >> #include >> #include >> #include >>+#include >> #include >> #include >> #include >>@@ -1506,41 +1507,32 @@ bool intel_dp_source_supports_tps4(struct drm_i915_private *i915) >> return DISPLAY_VER(i915) >= 10; >> } >> >>-static void snprintf_int_array(char *str, size_t len, >>- const int *array, int nelem) >>+static void seq_buf_print_array(struct seq_buf *s, const int *array, int nelem) >> { >> int i; >> >>- str[0] = '\0'; >>- >>- for (i = 0; i < nelem; i++) { >>- int r = snprintf(str, len, "%s%d", i ? ", " : "", array[i]); >>- if (r >= len) >>- return; >>- str += r; >>- len -= r; >>- } >>+ for (i = 0; i < nelem; i++) >>+ seq_buf_printf(s, "%s%d", i ? ", " : "", array[i]); >> } >> >> static void intel_dp_print_rates(struct intel_dp *intel_dp) >> { >>- struct drm_i915_private *i915 = dp_to_i915(intel_dp); >>- char str[128]; /* FIXME: too big for stack? */ >>+ struct intel_display *display = to_intel_display(intel_dp); >>+ DECLARE_SEQ_BUF(s, 128); /* FIXME: too big for stack? */ > > I wonder if just using drm_dbg_printer() would make things simpler, > without requiring a buffer. Mmh, that's always line based, isn't it? It would result in each rate getting printed on its own line, which is too spammy. > Anyway, the patch looks good to me, so: > > Reviewed-by: Gustavo Sousa Thanks! > >> >> if (!drm_debug_enabled(DRM_UT_KMS)) >> return; >> >>- snprintf_int_array(str, sizeof(str), >>- intel_dp->source_rates, intel_dp->num_source_rates); >>- drm_dbg_kms(&i915->drm, "source rates: %s\n", str); >>+ seq_buf_print_array(&s, intel_dp->source_rates, intel_dp->num_source_rates); >>+ drm_dbg_kms(display->drm, "source rates: %s\n", seq_buf_str(&s)); >> >>- snprintf_int_array(str, sizeof(str), >>- intel_dp->sink_rates, intel_dp->num_sink_rates); >>- drm_dbg_kms(&i915->drm, "sink rates: %s\n", str); >>+ seq_buf_clear(&s); >>+ seq_buf_print_array(&s, intel_dp->sink_rates, intel_dp->num_sink_rates); >>+ drm_dbg_kms(display->drm, "sink rates: %s\n", seq_buf_str(&s)); >> >>- snprintf_int_array(str, sizeof(str), >>- intel_dp->common_rates, intel_dp->num_common_rates); >>- drm_dbg_kms(&i915->drm, "common rates: %s\n", str); >>+ seq_buf_clear(&s); >>+ seq_buf_print_array(&s, intel_dp->common_rates, intel_dp->num_common_rates); >>+ drm_dbg_kms(display->drm, "common rates: %s\n", seq_buf_str(&s)); >> } >> >> static int forced_link_rate(struct intel_dp *intel_dp) >>-- >>2.39.5 >> -- Jani Nikula, Intel