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 26698CAC59A for ; Fri, 19 Sep 2025 10:27:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DCAEF10E987; Fri, 19 Sep 2025 10:27:34 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="McliW6a3"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) by gabe.freedesktop.org (Postfix) with ESMTPS id 34B1A10E987; Fri, 19 Sep 2025 10:27:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1758277654; x=1789813654; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=zHP6q2GkgapuSKRIBb7uv+I1RX7/6J9LsvIEoABTwSI=; b=McliW6a3ar8y/nfVo4HF3QEDSLTjORPiDReNRqv3RuBgIzF3DMt9csrp 963sa4A+j6eZFPmpUnC2LC/2utPM+nP6fcOY3j+efTS0uz+wqRcpyKA8l i2NuCOgSkVe0ilhrD/eRnssuyQED9fFdOYsaT+JU16TiRnhzEmNcPHOvS dLBncSMwysCnfEygprf73TPdQ46aXztxWq2TRJ2nXwp7opsoh6NV4Z0OQ 7pVT4XWF//7mfTPiaxqMBFts0MwAcUk/XpkvjsVxPM6UYm8WB8IPv6C1H TO3Dcn/iPZBxK1sqalTmgctr/zgS5FPc2A15TAKVXt7tX7AYH+1uOHKgq g==; X-CSE-ConnectionGUID: HXMX7qqWRlCLorGwnwYDIg== X-CSE-MsgGUID: 4boDnO3lSiuHOPiIypSJWg== X-IronPort-AV: E=McAfee;i="6800,10657,11531"; a="60569742" X-IronPort-AV: E=Sophos;i="6.17,312,1747724400"; d="scan'208";a="60569742" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2025 03:27:34 -0700 X-CSE-ConnectionGUID: +DYpuK63QjaJ9qFmKXaR3w== X-CSE-MsgGUID: PsUd6Kg/RWK7icDWAAXnTQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,277,1751266800"; d="scan'208";a="181076776" Received: from mjarzebo-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.246.222]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2025 03:27:31 -0700 From: Jani Nikula To: Suraj Kandpal , intel-xe@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: ankit.k.nautiyal@intel.com, Suraj Kandpal Subject: Re: [PATCH v2] drm/i915/ddi: Guard reg_val against a INVALID_TRANSCODER In-Reply-To: <20250908042208.1011144-1-suraj.kandpal@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20250908042208.1011144-1-suraj.kandpal@intel.com> Date: Fri, 19 Sep 2025 13:27:28 +0300 Message-ID: <002eef91ca8636d18f6d83482699c59e1e82e02e@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 Mon, 08 Sep 2025, Suraj Kandpal wrote: > Currently we check if the encoder is INVALID or -1 and throw a > WARN_ON but we still end up writing the temp value which will > overflow and corrupt the whole programmed value. > > --v2 > -Assign a bogus transcoder to master in case we get a INVALID > TRANSCODER [Jani] > > Fixes: 6671c367a9bea ("drm/i915/tgl: Select master transcoder for MST stream") > Signed-off-by: Suraj Kandpal Reviewed-by: Jani Nikula > --- > drivers/gpu/drm/i915/display/intel_ddi.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c > index 46017091bb0b..f67ce35c1c00 100644 > --- a/drivers/gpu/drm/i915/display/intel_ddi.c > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c > @@ -596,8 +596,9 @@ intel_ddi_transcoder_func_reg_val_get(struct intel_encoder *encoder, > enum transcoder master; > > master = crtc_state->mst_master_transcoder; > - drm_WARN_ON(display->drm, > - master == INVALID_TRANSCODER); > + if (drm_WARN_ON(display->drm, > + master == INVALID_TRANSCODER)) > + master = TRANSCODER_A; > temp |= TRANS_DDI_MST_TRANSPORT_SELECT(master); > } > } else { -- Jani Nikula, Intel