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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7050FECAAA1 for ; Mon, 31 Oct 2022 17:13:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231938AbiJaRM7 convert rfc822-to-8bit (ORCPT ); Mon, 31 Oct 2022 13:12:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231437AbiJaRM4 (ORCPT ); Mon, 31 Oct 2022 13:12:56 -0400 Received: from mail.inka.de (mail.inka.de [IPv6:2a04:c9c7:0:1073:217:a4ff:fe3b:e77c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 966E112D0E; Mon, 31 Oct 2022 10:12:54 -0700 (PDT) Received: from mail3.berkhan-weisser.de ([2a03:4000:54:b9a::4]) by mail.inka.de with esmtpsa id 1opYLE-003szj-4W; Mon, 31 Oct 2022 18:12:52 +0100 Received: from 127.0.0.1 (helo=localhost.localdomain) by mail3.berkhan-weisser.de with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.94.2) (envelope-from ) id 1opYLE-003e4Z-8i; Mon, 31 Oct 2022 18:12:51 +0100 Message-ID: Subject: Re: [PATCH v3 10/12] HID: ft260: wake up device from power saving mode From: Enrik Berkhan To: Michael Zaidman , jikos@kernel.org Cc: linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-i2c@vger.kernel.org, germain.hebert@ca.abb.com Date: Mon, 31 Oct 2022 18:12:51 +0100 In-Reply-To: <20221030203403.4637-11-michael.zaidman@gmail.com> References: <20221030203403.4637-1-michael.zaidman@gmail.com> <20221030203403.4637-11-michael.zaidman@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.44.4-0ubuntu1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Michael, On Sun, 2022-10-30 at 22:34 +0200, Michael Zaidman wrote: > The FT260 can enter a power saving mode after being idle for longer than > 5 seconds. > > When being woken up from power saving mode by an I2C write request, it > looks like a possible NACK will not be correctly reported back. As a > workaround, the driver will request an I2C status report before starting > the next I2C transfer if the FT260 has been idle for longer than 4800ms. Unfortunately, I have found issues with this patch as it is. When I tested from an installation running in KVM, I saw missed NACKs again. A possible fix seems to be to send the extra status request after the output report triggering the write. See https://github.com/MichaelZaidman/hid-ft260/pull/7. Cheers, Enrik