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=-7.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 E3726C433E0 for ; Fri, 8 Jan 2021 15:02:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4F3823A00 for ; Fri, 8 Jan 2021 15:02:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726740AbhAHPCf (ORCPT ); Fri, 8 Jan 2021 10:02:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:51536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725791AbhAHPCf (ORCPT ); Fri, 8 Jan 2021 10:02:35 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6308C23998; Fri, 8 Jan 2021 15:01:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610118115; bh=IILPEFi/JWzIYZ9DQVHDsq5/0esqom8SdyEIAwNmwXc=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=VyQwluAbAzP5cmcsiXwZK4buJGaiXfQbiYCyXPvzVNpP5JkIM5Ajxsml4O8PGkPbD V6D40Hc1fwIQ/XhR1fe34f2ZKSOD+Ro44mUjYYfAkNl9J3vNXOJIoNCeB6aIqbFUqH yoC2V84y6ajFhMvxhduYHJx/wBEz2WVNZ7yByYaqciwwb89/bnw+VoK2+fGzJZ3qLU dWlmtrF/eEgjk6WjjJPzgU4HTqc8hTQDtfL/jLfceuKho1DEQHq+zoOqcCSJbL269Z Tf1ofXpR0JX7epsys7wEIGjjZGkg5Zjgtuk+0vEjXORgBM/pHatHbQdVIw+SLL2zlF /6OOdb+3fAyLQ== Date: Fri, 8 Jan 2021 16:01:52 +0100 (CET) From: Jiri Kosina To: Hui Wang cc: linux-input@vger.kernel.org, benjamin.tissoires@redhat.com Subject: Re: [PATCH 2/2] HID: i2c-hid: Add a quirk to keep the power in shutdown In-Reply-To: <41f85551-96a6-7bac-6dc9-02a66080e900@canonical.com> Message-ID: References: <20201204152912.151604-1-hui.wang@canonical.com> <20201204152912.151604-2-hui.wang@canonical.com> <41f85551-96a6-7bac-6dc9-02a66080e900@canonical.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org On Thu, 7 Jan 2021, Hui Wang wrote: > >> On the latest Thinkpad Yoga laptop, the touchscreen module is wacom > >> I2C WACF2200 (056a:5276), we found the touchscreen could not work > >> after rebooting, needs to poweroff the machine then poweron the > >> machine to let it work. > >> > >> It is highly possible that this is a BIOS issue, but the windows > >> doesn't have this problem with the same BIOS. > >> > >> If keeping the power on when calling shutdown, the touchscreen could > >> work after rebooting. Let us add a quirk for it and apply the quirk > >> to this machine only. > > I wonder what do Windows do differently here. Perhaps they never put the > > i2c device to sleep while in shutdown anyway? Is there any downside to > > (not) doing the same? > > It is highly possible the Windows doesn't sleep the i2c device in shutdown. > When calling shutdown, it usually means reboot or poweroff the machine, so the > sleep is meaningless in this situation. In other situations like users > manually unload the i2c driver, maybe it will add a bit power consumption > without sleeping the device. Agreed, but if windows really don't put the device to sleep before shutting down, odds are there will be more devices behaving the same, and therefore we'd rather make it the default case instead of growing just another quirk list. > Anyway, I will try to ask for help from vendor, maybe they could provide > how Windows do when shutdown. Thank you, -- Jiri Kosina SUSE Labs