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 C1BE8C4332F for ; Mon, 28 Feb 2022 17:11:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233336AbiB1RMc (ORCPT ); Mon, 28 Feb 2022 12:12:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230161AbiB1RMa (ORCPT ); Mon, 28 Feb 2022 12:12:30 -0500 X-Greylist: delayed 30516 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 28 Feb 2022 09:11:51 PST Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [71.19.156.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86ABF7C177; Mon, 28 Feb 2022 09:11:51 -0800 (PST) Received: from hatter.bewilderbeest.net (174-21-187-98.tukw.qwest.net [174.21.187.98]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id 0B674516; Mon, 28 Feb 2022 09:11:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1646068311; bh=ka9wDIve8AgVIvxtisCTwLpRAivhzRXy0fQgcqAecRY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=g36pWvHrGTrqS2i2n5dld7CiuaGG1E3swlqbG5LA7YqJvrFR1AhzA8KOXZr8cXndQ xEYXORTroqutdHZWHhTDCvAy2lbviWmdk++/UAa9MpUJgI2XZZyWQcHj6ZwQO+75Hz 695lsE/Vv2AG9KsvfNpRlzqucWeawOfVf2JSZ3DI= Date: Mon, 28 Feb 2022 09:11:47 -0800 From: Zev Weiss To: Guenter Roeck Cc: linux-i2c@vger.kernel.org, Peter Rosin , Rob Herring , openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Wolfram Sang Subject: Re: [PATCH v2 0/2] ic2: mux: pca9541: add delayed-release support Message-ID: References: <20220201001810.19516-1-zev@bewilderbeest.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 28, 2022 at 05:57:27AM PST, Guenter Roeck wrote: >On 2/28/22 00:43, Zev Weiss wrote: >>On Mon, Jan 31, 2022 at 04:18:08PM PST, Zev Weiss wrote: >>>Hello, >>> >>>This series adds support for a new pca9541 device-tree property >>>("release-delay-us"), which delays releasing ownership of the bus >>>after a transaction for a configurable duration, anticipating that >>>another transaction may follow shortly.  By avoiding a >>>release/reacquisition between transactions, this can provide a >>>substantial performance improvement for back-to-back operations -- on >>>a Delta AHE-50DC (ASPEED AST1250) system running OpenBMC with dozens >>>of LM25066 PMICs on PCA9541-arbitrated busses, a setting of 10000 (10 >>>ms) reduces the median latency the psusensor daemon's hwmon sysfs file >>>reads from 2.28 ms to 0.99 ms (a 57% improvement). >>> >> >>Ping...Guenter, any thoughts on this? >> > >It sounds reasonable to me, but I don't have access to hardware anymore >to test it, so I have no means to confirm that it actually works. > Ack, thanks. In that case, what's the path forward on getting changes to this driver merged? I see sign-offs from Wolfram and Peter on the last few commits that touched it -- any input from the i2c/i2c-mux maintainers? Zev