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 07DFCC88E77 for ; Wed, 16 Sep 2026 08:29:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B1C4210E4E9; Wed, 16 Sep 2026 08:29:51 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="AgiKD7p+"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) by gabe.freedesktop.org (Postfix) with ESMTPS id 947CF10E4E9; Wed, 16 Sep 2026 08:29:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1789547391; x=1821083391; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=q29LIlsQVXv6z007U9sfBX2zs/XXZ9hXDfDUxaQSSf8=; b=AgiKD7p+Io5C51gtZH1xvJHC3OcJZF59PXFYpPvqpVKhg6qz4wRmvuvg 9xMI3+hZFaH13q1zebcaKiHIEoww1/a7qkw275NVAZvuG1uB2TEyhnSTJ 6DUnKbUr9CkVvM/63HyW/sz3TKyZgk1mjckA5ojwTTUcB4bW4hc/r4DDp R5wMaJBj/fsp0bdkOGwFTvyboZIu4+BtNhPomjI1cvfPIKogT8xlZkrET jeKsVy6rNl9bQeUCReRILAeT9m5NQxprH645lgIWlz8WZJDeSH8wIIory PwrRj9LIWmHNpePyra9D/sSK0NHHUeAFKp3+iBcy0CO8UHfHLR5nuxfK4 w==; X-CSE-ConnectionGUID: QcEO1TrATQGOnlERKqE3ww== X-CSE-MsgGUID: lTGokJz/TBqgM4e/Kzcmbw== X-IronPort-AV: E=McAfee;i="6800,10657,11905"; a="89858819" X-IronPort-AV: E=Sophos;i="6.27,103,1787036400"; d="scan'208";a="89858819" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Sep 2026 01:29:51 -0700 X-CSE-ConnectionGUID: L9a6+MV4R36bo6kCqgjYEw== X-CSE-MsgGUID: JibY11alTSSSLml5fOajyw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,103,1787036400"; d="scan'208";a="277017957" Received: from kniemiec-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.244.147]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Sep 2026 01:29:49 -0700 From: Jani Nikula To: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: jani.nikula@intel.com Subject: [PATCH 01/11] drm/i915/lspcon: use u8 variable to hold 1-byte DPCD reads Date: Wed, 16 Sep 2026 11:29:32 +0300 Message-ID: <66a74267a3da7619dda8dc2b1bb1bfcedc25df0d.1789547331.git.jani.nikula@intel.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland Content-Transfer-Encoding: 8bit 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" Passing a pointer to a u32 variable for a 1-byte reads is error prone, and only works because it's always initialized to 0 before the read, and the code's running on little-endian CPUs. Switch to u8 variables. In _lspcon_write_avi_infoframe_mca(), add a separate variable to hold the number of bytes written instead of reusing the same variable for two purposes. Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/display/intel_lspcon.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c index 9ceabbc981a1..b306bf5f6130 100644 --- a/drivers/gpu/drm/i915/display/intel_lspcon.c +++ b/drivers/gpu/drm/i915/display/intel_lspcon.c @@ -435,14 +435,14 @@ static bool _lspcon_write_avi_infoframe_parade(struct drm_dp_aux *aux, static bool _lspcon_write_avi_infoframe_mca(struct drm_dp_aux *aux, const u8 *buffer, ssize_t len) { - int ret; - u32 val = 0; + int ret, written = 0; u32 retry; u16 reg; const u8 *data = buffer; + u8 val; reg = LSPCON_MCA_AVI_IF_WRITE_OFFSET; - while (val < len) { + while (written < len) { /* DPCD write for AVI IF can fail on a slow FW day, so retry */ for (retry = 0; retry < 5; retry++) { ret = drm_dp_dpcd_write(aux, reg, (void *)data, 1); @@ -456,7 +456,9 @@ static bool _lspcon_write_avi_infoframe_mca(struct drm_dp_aux *aux, return false; } } - val++; reg++; data++; + written++; + reg++; + data++; } val = 0; @@ -612,8 +614,8 @@ void lspcon_set_infoframes(struct intel_encoder *encoder, static bool _lspcon_read_avi_infoframe_enabled_mca(struct drm_dp_aux *aux) { int ret; - u32 val = 0; u16 reg = LSPCON_MCA_AVI_IF_CTRL; + u8 val; ret = drm_dp_dpcd_read(aux, reg, &val, 1); if (ret < 0) { @@ -627,8 +629,8 @@ static bool _lspcon_read_avi_infoframe_enabled_mca(struct drm_dp_aux *aux) static bool _lspcon_read_avi_infoframe_enabled_parade(struct drm_dp_aux *aux) { int ret; - u32 val = 0; u16 reg = LSPCON_PARADE_AVI_IF_CTRL; + u8 val; ret = drm_dp_dpcd_read(aux, reg, &val, 1); if (ret < 0) { -- 2.47.3