From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752075Ab1GERmn (ORCPT ); Tue, 5 Jul 2011 13:42:43 -0400 Received: from adelie.canonical.com ([91.189.90.139]:48852 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750749Ab1GERmm (ORCPT ); Tue, 5 Jul 2011 13:42:42 -0400 Message-ID: <4E134D0C.7060500@canonical.com> Date: Tue, 05 Jul 2011 10:42:36 -0700 From: Chase Douglas User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110516 Thunderbird/3.1.10 MIME-Version: 1.0 To: djkurtz@chromium.org CC: dmitry.torokhov@gmail.com, rydberg@euromail.se, rubini@cvml.unipv.it, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, derek.foreman@collabora.co.uk, daniel.stone@collabora.co.uk, olofj@chromium.org Subject: Re: [PATCH 02/12] Input: synaptics - do not invert y if 0 References: <1309324042-22943-1-git-send-email-djkurtz@chromium.org> <1309324042-22943-3-git-send-email-djkurtz@chromium.org> In-Reply-To: <1309324042-22943-3-git-send-email-djkurtz@chromium.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/28/2011 10:07 PM, djkurtz@chromium.org wrote: > From: Daniel Kurtz > > Synaptics touchpads report increasing y from bottom to top. > This is inverted from normal userspace "top of screen is 0" coordinates. > Thus, the kernel driver reports inverted y coordinates to userspace. > > In some cases, however, y = 0 is sent by the touchpad. > In these cases, the kernel driver should not invert, and just report 0. Under what cases is y sent as 0, and why do we want to report it as 0 to userspace? > > This patch also refactors the inversion into a macro, and moves it > into packet processing instead of during position reporting. It's getting really hard to read the bit transformations with a macro. I'd prefer an approach that splits the computation. Maybe: hw->y = bit_manipulations; hw->y = INVERT_Y(hw->y); (could use a temporary variable too) Or maybe define a static inline function that takes the hw state as an arg: hw->y = bit_manipulations; fix_y(hw); I'd prefer this implementation if every scenario involved manipulating the y value of the hw state struct. Also, it would be great if you could add your explanation of why Y is inverted as a comment above INVERT_Y (or whatever function/macro it eventually becomes). Thanks! -- Chase > Signed-off-by: Daniel Kurtz > --- > drivers/input/mouse/synaptics.c | 16 +++++++++------- > 1 files changed, 9 insertions(+), 7 deletions(-) > > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c > index e06e045..f6d0c04 100644 > --- a/drivers/input/mouse/synaptics.c > +++ b/drivers/input/mouse/synaptics.c > @@ -44,6 +44,8 @@ > #define YMIN_NOMINAL 1408 > #define YMAX_NOMINAL 4448 > > +#define INVERT_Y(y) (((y) != 0) ? (YMAX_NOMINAL + YMIN_NOMINAL - (y)) : 0) > + > > /***************************************************************************** > * Stuff we need even when we do not want native Synaptics support > @@ -409,9 +411,9 @@ static int synaptics_parse_hw_state(const unsigned char buf[], > hw->x = (((buf[3] & 0x10) << 8) | > ((buf[1] & 0x0f) << 8) | > buf[4]); > - hw->y = (((buf[3] & 0x20) << 7) | > + hw->y = INVERT_Y((((buf[3] & 0x20) << 7) | > ((buf[1] & 0xf0) << 4) | > - buf[5]); > + buf[5])); > > hw->z = buf[2]; > hw->w = (((buf[0] & 0x30) >> 2) | > @@ -421,7 +423,8 @@ static int synaptics_parse_hw_state(const unsigned char buf[], > if (SYN_CAP_ADV_GESTURE(priv->ext_cap_0c) && hw->w == 2) { > /* Gesture packet: (x, y, z) at half resolution */ > priv->mt.x = (((buf[4] & 0x0f) << 8) | buf[1]) << 1; > - priv->mt.y = (((buf[4] & 0xf0) << 4) | buf[2]) << 1; > + priv->mt.y = INVERT_Y((((buf[4] & 0xf0) << 4) > + | buf[2]) << 1); > priv->mt.z = ((buf[3] & 0x30) | (buf[5] & 0x0f)) << 1; > return 1; > } > @@ -473,7 +476,7 @@ static int synaptics_parse_hw_state(const unsigned char buf[], > } > } else { > hw->x = (((buf[1] & 0x1f) << 8) | buf[2]); > - hw->y = (((buf[4] & 0x1f) << 8) | buf[5]); > + hw->y = INVERT_Y(((buf[4] & 0x1f) << 8) | buf[5]); > > hw->z = (((buf[0] & 0x30) << 2) | (buf[3] & 0x3F)); > hw->w = (((buf[1] & 0x80) >> 4) | ((buf[0] & 0x04) >> 1)); > @@ -491,8 +494,7 @@ static void set_slot(struct input_dev *dev, int slot, bool active, int x, int y) > input_mt_report_slot_state(dev, MT_TOOL_FINGER, active); > if (active) { > input_report_abs(dev, ABS_MT_POSITION_X, x); > - input_report_abs(dev, ABS_MT_POSITION_Y, > - YMAX_NOMINAL + YMIN_NOMINAL - y); > + input_report_abs(dev, ABS_MT_POSITION_Y, y); > } > } > > @@ -584,7 +586,7 @@ static void synaptics_process_packet(struct psmouse *psmouse) > > if (num_fingers > 0) { > input_report_abs(dev, ABS_X, hw.x); > - input_report_abs(dev, ABS_Y, YMAX_NOMINAL + YMIN_NOMINAL - hw.y); > + input_report_abs(dev, ABS_Y, hw.y); > } > input_report_abs(dev, ABS_PRESSURE, hw.z); >