Received: by 2002:a05:6359:c8b:b0:c7:702f:21d4 with SMTP id go11csp2258766rwb; Wed, 5 Oct 2022 11:20:55 -0700 (PDT) X-Google-Smtp-Source: AMsMyM7HiM1UMTsAT4YZXtl0WAw0vVwnC01kUHqPV4anPq8/oc5cIOUM2KpbvjIYujFHeiTd9xr2 X-Received: by 2002:a05:6402:4282:b0:459:befa:c79c with SMTP id g2-20020a056402428200b00459befac79cmr996905edc.23.1664994055040; Wed, 05 Oct 2022 11:20:55 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1664994055; cv=none; d=google.com; s=arc-20160816; b=1KEICEaz2S6tJUqPyKlevBsPopiQnZa4xRRrPFBBHHgdQY97mmIFPCvqzzlQps80Tz E10lBavvMuVFIhNLWZDNO5qv/yLvUGji0xihTC4RivU+EQ4/Cns08/LlSunhSI7BCkmU XDiY0ee7Om+GHPG9zRrKHSE1TuvxTj7kcX9umG+40DmImUGJpGYyB+aGJbTsKSAbdjFd fT5lx7ex2pSJ58c3cU98ATduYXr1oFk8HVoYbeOvLytc1QC5M4iyJNR55uL5f/dtYN7j gA58TPEoM0WUmzT09ybo2oG6bJROpRpQTLNdumeEsGP8LmpDXXFmRi8xK91nKg4oKw4C vlaA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:user-agent :content-transfer-encoding:references:in-reply-to:date:cc:to:from :subject:message-id; bh=+CJI4jevxrTwJm1U6eiSKjdzoV+104KGR1IdoheCxEQ=; b=jLqruSIh1DKyqM9eTRAL+njKaXsXn13/y8VbRxwVb5bDW1+F26SZ6hVqNQEUmcvtX3 3fKXHIXXSt58d4jFY+88I9QOC4tlBDLJKsgmCczqU+b3b3quudc5g/SXgJYqkRsdgSwv i+ZVrWc3EhgUcnHXjFEzx0avBUBp1w5I8Ap70lsvVTA9Y1TcvenU1kgzRDGRX9aGGsMe zbvFmdQa2gOtZSPTvaBrwLmaayqCHPOdnrJQFy+lf0H1cTM6dhMMK+AAlvFmZ6qc05tD OceDc8I4tnlq7MGbeHyz4jyQa1NSOtIZ9soC6d6F4qA0Tu6YTfrqbYhOW7Jf7kd8zfQ/ FwVw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id qw23-20020a1709066a1700b007708617c995si14747459ejc.339.2022.10.05.11.20.28; Wed, 05 Oct 2022 11:20:55 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229722AbiJEST0 convert rfc822-to-8bit (ORCPT + 99 others); Wed, 5 Oct 2022 14:19:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229797AbiJESTU (ORCPT ); Wed, 5 Oct 2022 14:19:20 -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 C20217F27C; Wed, 5 Oct 2022 11:19:18 -0700 (PDT) Received: from mail3.berkhan-weisser.de ([2a03:4000:54:b9a::4]) by mail.inka.de with esmtpsa id 1og8zE-001sH4-Ga; Wed, 05 Oct 2022 20:19:16 +0200 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 1og8zE-00BKTP-4E; Wed, 05 Oct 2022 20:19:16 +0200 Message-ID: <6ebd7f9424e43c70af4ada9fe5bf616d1a112bcc.camel@inka.de> Subject: Re: [PATCH v2 5/7] HID: ft260: improve i2c large reads performance From: Enrik Berkhan To: Michael Zaidman Cc: jikos@kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, Guillaume Champagne Date: Wed, 05 Oct 2022 20:19:15 +0200 In-Reply-To: References: <20220928144854.5580-1-michael.zaidman@gmail.com> <20220928144854.5580-6-michael.zaidman@gmail.com> <4ce2960686605f2290046b396a8edc4cc47beb9e.camel@inka.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.44.1-0ubuntu1 MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_NONE, SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Michael, On Wed, 2022-10-05 at 17:34 +0300, Michael Zaidman wrote: > On Tue, Oct 04, 2022 at 08:15:56PM +0200, Enrik Berkhan wrote: > > As the ft260 can pack up to 60 bytes into one report, would it make > > sense to use a multiple-of-60 size (120 or 180)? Might reduce overhead > > by another tiny bit ... > > > > Cheers, > > Enrik > > > The size of the Read IO to perform is given to the driver by the upper > layer. So it's up to him how to align the IO request size. > > When we read from the EEPROM, we want to issue the read requests with > EEPROM page size granularity. The I2C EEPROMs page sizes are usually a > power of 2 aligned. Understood! I only thought about the HID report sizes. With EEPROMs etc. in mind, it makes perfect sense to prefer power of 2 sizes. Thanks for also providing the test results. Cheers, Enrik