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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E818C432C0 for ; Tue, 19 Nov 2019 05:18:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45E1222318 for ; Tue, 19 Nov 2019 05:18:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="c7Kdgz48" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726775AbfKSFSy (ORCPT ); Tue, 19 Nov 2019 00:18:54 -0500 Received: from mail-vk1-f193.google.com ([209.85.221.193]:37618 "EHLO mail-vk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725280AbfKSFSw (ORCPT ); Tue, 19 Nov 2019 00:18:52 -0500 Received: by mail-vk1-f193.google.com with SMTP id l5so4740591vkb.4 for ; Mon, 18 Nov 2019 21:18:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jDmWyWEB6X6hwrCpbp9uiQYwQF5jG8Fol62ACoWdqew=; b=c7Kdgz48g3DqmoLb5/0VghHmU09mTfosgKrO2YFfZPUvxt/RdRNli50PhjfWMgc4ne uonk3fenlMZy18GUcL68KuWUqJPsoMMCbzpudzypbhBT6G7/5MjrqMYVVh3gDukcvMoZ LbeoSYrtDWSK0Y9udIKVMAzyn/shXDgGetomc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jDmWyWEB6X6hwrCpbp9uiQYwQF5jG8Fol62ACoWdqew=; b=lIVFTvo/s6Ox0gfA5IqzBNyFRVHZSAYA6XmXQAG1iosTPZxCjusoON9Jag7C4Uc6mt iwe7d0xCadrbHVbSnyMnXXCWnTJoQ+yb27GsN0yRQicF9iD2A87r1eV6VZob3ea3MMgu 4a4MFCz3ze8lqWKYthogk2xCVEVJ07DJcAf9tAi8ePrBNZvS++u+Zssn6eccCg+ua/r5 /jhKW1kTPW65aCilKyXp1yZzXc5uCMg24Y/frReUwwgSF6Y2L5qFGnm8kkIxASiQbSUI r+2SrDxYFlQ6e/Xx1gpsUq2jAKiy9A1GrNlf0Xa1ELwnvG7Futa1z7HDZ31E0rDEN1Y5 bVBg== X-Gm-Message-State: APjAAAUJMP9noO28g1i8AAQGoW2xSzgSasxWfLpA239ZZFNqqWlvEx2T B8vs61reCnB6rzxwWhXNu0MTot5ChOUTKhjxvfgizA== X-Google-Smtp-Source: APXvYqzmN805E8eN41XyzvJqz/8UfDTMFSoZBSua6kbhailEbajnHsqg9CvbSCG2iONWHTyO5oZA5JWDZTSYdRVIGRE= X-Received: by 2002:a1f:2556:: with SMTP id l83mr18367851vkl.77.1574140729713; Mon, 18 Nov 2019 21:18:49 -0800 (PST) MIME-Version: 1.0 References: <20191117033149.259303-1-ikjn@chromium.org> In-Reply-To: From: Ikjoon Jang Date: Tue, 19 Nov 2019 13:18:38 +0800 Message-ID: Subject: Re: [PATCH 0/2] usb: override hub device bInterval with device node To: Alan Stern Cc: linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Rob Herring , Mark Rutland , Suwan Kim , "Gustavo A . R . Silva" , Johan Hovold , Nicolas Boitchat Content-Type: text/plain; charset="UTF-8" Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Sun, Nov 17, 2019 at 11:46 PM Alan Stern wrote: > > On Sun, 17 Nov 2019, Ikjoon Jang wrote: > > > This patchset enables hard wired hub device to use different bInterval > > from its descriptor when the hub has a combined device node. > > > > When we know the specific hard wired hub supports changing its polling > > interval, we can adjust hub's interval to reduce the time of waking up > > from autosuspend or connect detection of HIDs. > > In fact, _all_ hubs support changing the polling interval. The value > given in the USB spec is just an upper limit; any smaller value is > equally acceptable. > > So why are you doing this only for hard-wired hubs? Why not for all > hubs? Because we only want to apply it to a specific device instance under our control. We apply autosuspend to built-in touchpad device for power savings, Users can attach external hub devices with same VID:PID that we don't want to change the behavior. Maybe disabling autosuspend for external HIDs can be more reasonable for that case? > > And is 250 ms really too long to wait for remote wakeup or connect > detection? What's the real motivation behind this change? When a user starts to move the cursor while touchpad is in autosuspend state, It takes more than >250ms (worst case can be >500ms) to wake up and response. That makes the cursor stuck for a while and warp to another location suddenly. Thanks. > > Alan Stern >