From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5ADA7226888 for ; Thu, 8 May 2025 12:16:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746706596; cv=none; b=cyntqQBIaUWxX4Y+Px0YRJej6XjByXo7sANz7/1cEFGJQ/+UvJ5bzdgZOCqzFnCS6Tygth/hG7SYUVUnIPWo5frKe4HaRD0fz0pRuGbNUh5Y/u4PiseRESeoYKl7dWfDI/vUnin5FqaV3acfE9kfV7A/UyQoTl/ekXPIgaUSPZw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746706596; c=relaxed/simple; bh=7X3Ofin17uEXRiWR2/7qF07FRRAOt7jou2NssZWBl6g=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=MN48t44V4Ben7srOJFgSReql3/cfN3qfliir8fHYrksHndtIIoQZLv6CBddYLX/AwmydTiI7LPv0MEeZH8OsLApCnY6w1+MOshBYu7BmbwzHxwftG+jNyp3Lr1L3e68fJowwu9fr/39HxeolIv+Wo/rgppzoW0O7DoMNDa2y7Qo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=g2dNpDDU; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="g2dNpDDU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1746706594; x=1778242594; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=7X3Ofin17uEXRiWR2/7qF07FRRAOt7jou2NssZWBl6g=; b=g2dNpDDU3NroTh0bAzIWbK2+zEznQhwpIZuHvBAASaRY42sRV19L/7+q U97FUUSbl0XrJ3w+DRXcFCBdpmtlmbiEBshfuWGkUWPBXiQRGjDjFJ9bN pwntCsmB4il74s7WHJuThGCTBcCetqy6pGT3aVYq0p+uJ7tExCfdcrXcT U/Jqhv1Kb50E6XTZkIGbADIL8TBKUcw3j7vSBJagRuRBZWP+Oun+fRm3W /ykBGZ5bGr/8DezwvbwkQcvL8EYkEQmKrjMBvCRkjjbtpK0y5h871Hw1A TJd8F3+rIoV0HnBADJ/ukjl41aeLDWY+amUar40sjPor+sdtHuWAa4VzM w==; X-CSE-ConnectionGUID: w1O0OFq7Qo+shJNXwjvyJw== X-CSE-MsgGUID: 91L/W7paRFq/pjIbTAk6ww== X-IronPort-AV: E=McAfee;i="6700,10204,11426"; a="52293828" X-IronPort-AV: E=Sophos;i="6.15,272,1739865600"; d="scan'208";a="52293828" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2025 05:16:33 -0700 X-CSE-ConnectionGUID: TkJmIs6ESgGmq2EEtRNiMA== X-CSE-MsgGUID: pKn7x70CTz2Q/Gwd5rNzlA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,272,1739865600"; d="scan'208";a="136206747" Received: from unknown (HELO localhost) ([10.237.66.160]) by fmviesa006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2025 05:16:32 -0700 From: Jani Nikula To: "Lin, Wayne" , "dri-devel@lists.freedesktop.org" Cc: "ville.syrjala@linux.intel.com" , "Limonciello, Mario" , "Wentland, Harry" , "stable@vger.kernel.org" Subject: RE: [PATCH] drm/dp: Fix Write_Status_Update_Request AUX request format In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20250427095053.875064-1-Wayne.Lin@amd.com> <877c2rv7k3.fsf@intel.com> Date: Thu, 08 May 2025 15:16:29 +0300 Message-ID: <878qn7ti02.fsf@intel.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Thu, 08 May 2025, "Lin, Wayne" wrote: > [Public] > >> -----Original Message----- >> From: Jani Nikula >> Sent: Thursday, May 8, 2025 4:19 PM >> To: Lin, Wayne ; dri-devel@lists.freedesktop.org >> Cc: ville.syrjala@linux.intel.com; Limonciello, Mario ; >> Wentland, Harry ; Lin, Wayne >> ; stable@vger.kernel.org >> Subject: Re: [PATCH] drm/dp: Fix Write_Status_Update_Request AUX request >> format >> >> On Sun, 27 Apr 2025, Wayne Lin wrote: >> > + /* >> > + * When I2C write firstly get defer and get ack after >> > + * retries by wirte_status_update, we have to return >> > + * all data bytes get transferred instead of 0. >> > + */ >> >> My brain gives me syntax and parse error here. ;) > > Appreciate for the feedback, Jani. > Could you elaborate more on your concerns please? > > Since Write_Status_Update_Request is address only request. Data length > is 0. When I2C write request completes, reply for > Write_Status_Update_Request from DPRx will be ACK only (i.e. data > length is 0). > > Is your concern about returning 0 from aux->transfer? > My thoughts is drm_dp_i2c_do_msg() is designed to handle I2C-Over-Aux > reply data, and aux->transfer() is handling hw specific manipulation and > return transferred bytes. For Write_Status_Update_Request request itself, > nothing new to be transferred. I think drm_dp_i2c_do_msg() should be > responsible for determining the correct transferred data bytes under this > case. Or do you expect aux->transfer to memorize the data length of > write request? My concern is that I don't understand what the comment is trying to say. "when i2c write firstly get defer" - what does it mean? "wirte_status_update" - typo "we have to" - why? "return all data bytes get transferred" - what does it mean? > > Thanks! >> >> BR, >> Jani. >> >> -- >> Jani Nikula, Intel > -- > Wayne Lin -- Jani Nikula, Intel