Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:57514 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751255Ab2AQJnK convert rfc822-to-8bit (ORCPT ); Tue, 17 Jan 2012 04:43:10 -0500 From: "Elias, Ilan" To: Samuel Ortiz CC: "aloisio.almeida@openbossa.org" , "lauro.venancio@openbossa.org" , "linville@tuxdriver.com" , "linux-wireless@vger.kernel.org" Subject: RE: [PATCH] NFC: Increase NCI deactivate timeout Date: Tue, 17 Jan 2012 09:42:56 +0000 Message-ID: (sfid-20120117_104314_848673_F44647F4) References: <1326022982-30205-1-git-send-email-ilane@ti.com> <1326745622.22824.12.camel@sortiz-mobl> In-Reply-To: <1326745622.22824.12.camel@sortiz-mobl> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi Samuel, > > Increase NCI deactivate timeout from 5 sec to 30 sec. > > NCI deactivate procedure might take a long time, > > depending on the local and remote parameters. > 30 seconds sounds like a huge delay for receiving a reply to > such command. > Would you care explaining how we can get that long of a timeout ? The controller in the Reader side uses a value called nRETRY (see NFC Forum Digital spec). This value is an internal implementation, valid range is 2 to 5. This value determines the number of re-transmissions. The controller in the Tag side uses a value called FWI - Frame Waiting time Integer (see NFC Forum Digital spec). This value is an internal implementation, valid range is 1 to 14. This value determines (via some formula) the FWT - Frame Waiting Time, which is a timout. Max FWT value can be almost 5sec. So, the total max timeout can be 5sec for the first packet + 5sec for each of the 5 re-transmissions = 5 + 5x5 = 30 sec. > Cheers, > Samuel. Thanks & BR, Ilan