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 5DC24105F7B5 for ; Fri, 13 Mar 2026 15:41:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DDA1210E45A; Fri, 13 Mar 2026 15:41:32 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="YIH9SLf7"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) by gabe.freedesktop.org (Postfix) with ESMTPS id A824710E45B; Fri, 13 Mar 2026 15:41:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773416492; x=1804952492; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=CxVN9VlC3SWpg1TmlHV0rqFxt6d7g9UyQXojpSvD4QA=; b=YIH9SLf7MJp1Hx0uF9Osd/tUyADGGgQKA+WgDPmfRAUYEeGNbm0vA9tC dpZ/AMaxdcuOAgMHOOFfsFcjgMXNw0VS34shgmvvDkaTEgNP7sywOsnc2 oYBduAylAT82kkJbcpiwCVzcERRgPFzd+aP0t239RrDEv0pdC+gA8cJKk GclK4zevbzqcrQlgJzqVuNe0hAHTY7Ba4iyiasuQL+6vLSyt6QOADMIi8 zl/toOJdheEGCT9qYfsmfYVegJ4VkVSSgsGyCuYksFrjzTdUgi9qBm4d1 JkRFMqEP+HTEb4i7Xml3TpN4I27/S5evtGDAgNDihkfVxUKOCZsYf6km6 g==; X-CSE-ConnectionGUID: PVHuaNTMSdSahwp7x9MhIg== X-CSE-MsgGUID: n1toCIjpT5qJ59ZzMz1/7Q== X-IronPort-AV: E=McAfee;i="6800,10657,11728"; a="78417456" X-IronPort-AV: E=Sophos;i="6.23,118,1770624000"; d="scan'208";a="78417456" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Mar 2026 08:41:31 -0700 X-CSE-ConnectionGUID: 4/iwgC4OT/KcDRjcM8Kv3Q== X-CSE-MsgGUID: 7ApDyu/QSg2Yjbtz69TiSQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,118,1770624000"; d="scan'208";a="259098318" Received: from mjarzebo-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.246.193]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Mar 2026 08:41:27 -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 , Gustavo Sousa , =?utf-8?Q?Micha=C5=82?= Grzelak , Rodrigo Vivi Subject: Re: [PATCH 1/2] drm/i915/cx0: Clear response ready & error bit In-Reply-To: <20260122044859.753682-1-suraj.kandpal@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland References: <20260122044859.753682-1-suraj.kandpal@intel.com> Date: Fri, 13 Mar 2026 17:41:23 +0200 Message-ID: <4246db6c7096dd089ebcd7ac0b3c7589a232e836@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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" On Thu, 22 Jan 2026, Suraj Kandpal wrote: > Clear the response ready and error bit of PORT_P2M_MESSAGE_BUS_STATUS > before writing the transaction pending bit of > PORT_M2P_MSGBUS_CTL as that is a hard requirement. If not done > we find that the PHY hangs since it ends up in a weird state if left > idle for more than 1 hour. Should this have had a Fixes: tag or Cc: stable like Rodrigo asked way back when [1]? Do we have some PHY hang issue in the wild? We rely heavily on developers identifying fixes that need backports to stable kernels. BR, Jani. [1] https://lore.kernel.org/r/aWexzTR221l0F-we@intel.com > > Bspec: 65101 > Signed-off-by: Suraj Kandpal > Reviewed-by: Gustavo Sousa > Reviewed-by: Micha=C5=82 Grzelak > --- > drivers/gpu/drm/i915/display/intel_cx0_phy.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/d= rm/i915/display/intel_cx0_phy.c > index 4f56a370102d..ff74f64eb970 100644 > --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c > +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c > @@ -223,6 +223,8 @@ static int __intel_cx0_read_once(struct intel_encoder= *encoder, > return -ETIMEDOUT; > } >=20=20 > + intel_clear_response_ready_flag(encoder, lane); > + > intel_de_write(display, XELPDP_PORT_M2P_MSGBUS_CTL(display, port, lane), > XELPDP_PORT_M2P_TRANSACTION_PENDING | > XELPDP_PORT_M2P_COMMAND_READ | > @@ -294,6 +296,8 @@ static int __intel_cx0_write_once(struct intel_encode= r *encoder, > return -ETIMEDOUT; > } >=20=20 > + intel_clear_response_ready_flag(encoder, lane); > + > intel_de_write(display, XELPDP_PORT_M2P_MSGBUS_CTL(display, port, lane), > XELPDP_PORT_M2P_TRANSACTION_PENDING | > (committed ? XELPDP_PORT_M2P_COMMAND_WRITE_COMMITTED : --=20 Jani Nikula, Intel