Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755648Ab0HaU6r (ORCPT ); Tue, 31 Aug 2010 16:58:47 -0400 Received: from adelie.canonical.com ([91.189.90.139]:46985 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911Ab0HaU6p (ORCPT ); Tue, 31 Aug 2010 16:58:45 -0400 Subject: Re: [PATCH 4/6 v2] HID: magicmouse: remove axis data filtering From: Chase Douglas To: Henrik Rydberg Cc: Jiri Kosina , Michael Poole , Tejun Heo , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <4C7D6739.5000601@euromail.se> References: <1283280068-12285-1-git-send-email-chase.douglas@canonical.com> <1283280068-12285-4-git-send-email-chase.douglas@canonical.com> <4C7D6739.5000601@euromail.se> Content-Type: text/plain; charset="UTF-8" Date: Tue, 31 Aug 2010 16:58:39 -0400 Message-ID: <1283288319.2255.103.camel@mini> Mime-Version: 1.0 X-Mailer: Evolution 2.30.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3029 Lines: 70 On Tue, 2010-08-31 at 22:34 +0200, Henrik Rydberg wrote: > On 08/31/2010 08:41 PM, Chase Douglas wrote: > > > The Magic Mouse device is very precise. No driver filtering of input > > data needs to be performed. > > > > Signed-off-by: Chase Douglas > > Acked-by: Michael Poole > > --- > > > I am still not sure this is a good idea. Bandwidth from MT devices is a big > deal. A statement roughly how much data comes out of mtdev (which does the > filtering for type A devices) before and after this change would be reassuring. As it is right now, hid-magicmouse doesn't support MT slots. I think all the fuzz code ends up comparing in the MT case is between one touch and another touch, not between one touch's current location and its previous location. If I'm correct, then it means a fuzz > 0 is incorrect for non-slotted MT devices. In fact, the code in drivers/input/input.c around line 194 looks like it discards defuzzing in this case, so one could say this patch is making things more correct :). Now a fuzz > 0 for the non-MT ABS axes may be useful, but this device exhibits no jitter, and we're not really worried about bandwidth in the single touch case. -- Chase > > drivers/hid/hid-magicmouse.c | 10 +++++----- > > 1 files changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c > > index 98bbc53..0fe2464 100644 > > --- a/drivers/hid/hid-magicmouse.c > > +++ b/drivers/hid/hid-magicmouse.c > > @@ -357,11 +357,11 @@ static void magicmouse_setup_input(struct input_dev *input, struct hid_device *h > > __set_bit(EV_ABS, input->evbit); > > > > input_set_abs_params(input, ABS_MT_TRACKING_ID, 0, 15, 0, 0); > > - input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255, 4, 0); > > - input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 255, 4, 0); > > - input_set_abs_params(input, ABS_MT_ORIENTATION, -32, 31, 1, 0); > > + input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0); > > + input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0); > > + input_set_abs_params(input, ABS_MT_ORIENTATION, -32, 31, 0, 0); > > input_set_abs_params(input, ABS_MT_POSITION_X, -1100, 1358, > > - 4, 0); > > + 0, 0); > > /* Note: Touch Y position from the device is inverted relative > > * to how pointer motion is reported (and relative to how USB > > * HID recommends the coordinates work). This driver keeps > > @@ -369,7 +369,7 @@ static void magicmouse_setup_input(struct input_dev *input, struct hid_device *h > > * inverse of the reported Y. > > */ > > input_set_abs_params(input, ABS_MT_POSITION_Y, -1589, 2047, > > - 4, 0); > > + 0, 0); > > } > > > > if (report_undeciphered) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/