From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52850 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753364AbdGCLcw (ORCPT ); Mon, 3 Jul 2017 07:32:52 -0400 Subject: Patch "HID: i2c-hid: Add sleep between POWER ON and RESET" has been added to the 4.4-stable tree To: redmcg@redmandi.dyndns.org, alexander.levin@verizon.com, benjamin.tissoires@redhat.com, gregkh@linuxfoundation.org, jkosina@suse.cz Cc: , From: Date: Mon, 03 Jul 2017 13:32:40 +0200 Message-ID: <1499081560320@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled HID: i2c-hid: Add sleep between POWER ON and RESET to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hid-i2c-hid-add-sleep-between-power-on-and-reset.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Mon Jul 3 13:29:24 CEST 2017 From: Brendan McGrath Date: Sat, 7 Jan 2017 08:01:38 +1100 Subject: HID: i2c-hid: Add sleep between POWER ON and RESET From: Brendan McGrath [ Upstream commit a89af4abdf9b353cdd6f61afc0eaaac403304873 ] Support for the Asus Touchpad was recently added. It turns out this device can fail initialisation (and become unusable) when the RESET command is sent too soon after the POWER ON command. Unfortunately the i2c-hid specification does not specify the need for a delay between these two commands. But it was discovered the Windows driver has a 1ms delay. As a result, this patch modifies the i2c-hid module to add a sleep inbetween the POWER ON and RESET commands which lasts between 1ms and 5ms. See https://github.com/vlasenko/hid-asus-dkms/issues/24 for further details. Signed-off-by: Brendan McGrath Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/hid/i2c-hid/i2c-hid.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -364,6 +364,15 @@ static int i2c_hid_hwreset(struct i2c_cl if (ret) return ret; + /* + * The HID over I2C specification states that if a DEVICE needs time + * after the PWR_ON request, it should utilise CLOCK stretching. + * However, it has been observered that the Windows driver provides a + * 1ms sleep between the PWR_ON and RESET requests and that some devices + * rely on this. + */ + usleep_range(1000, 5000); + i2c_hid_dbg(ihid, "resetting...\n"); ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0); Patches currently in stable-queue which might be from redmcg@redmandi.dyndns.org are queue-4.4/hid-i2c-hid-add-sleep-between-power-on-and-reset.patch