From mboxrd@z Thu Jan 1 00:00:00 1970 From: simon@mungewell.org Subject: Re: Multiple clients reading from /dev/input/eventX Date: Wed, 24 Oct 2012 00:26:17 -0400 Message-ID: References: <20121019223210.GA10915@core.coreip.homeip.net> Mime-Version: 1.0 Content-Type: multipart/mixed;boundary="----=_20121024002616_92581" Return-path: Received: from host171.canaca.com ([67.55.55.225]:44405 "EHLO host171.canaca.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750723Ab2JXE0S (ORCPT ); Wed, 24 Oct 2012 00:26:18 -0400 In-Reply-To: <20121019223210.GA10915@core.coreip.homeip.net> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: simon@mungewell.org, linux-input@vger.kernel.org ------=_20121024002616_92581 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit >> Can anyone here confirm the behaviour under the situation that one >> client >> is busy? What is the maximum time it can be 'away' or what is the size >> of >> the inline buffer? > > Every user of event device has a buffer that can hold up at least 64 > input events and is completely independent from other users. Newer > kernels generate EV_SYN/SYN_DROPPED event to indicate that user was too > slow reading data and there was buffer overrun. > > Hope this helps. Yes, very helpful.... I am seeing 'SYN_DROPPED' on my system, so the next question is how to work around this? In the event of an overflow is there any method of reading/polling the last (correct) event value for each of the axis? In my case on the G27 wheel when your foot transitions from the brake to accelerator, you get no more 'brake events' to 'refresh' the value. I see that I could use QUIRK to enlarge the buffer for this device, would that be an acceptable workaround? http://www.spinics.net/lists/linux-input/msg15497.html Attached is a little log showing SDL 'missing' 68 events, which are correctly reported by 'evtest'. The time stamps in log will give you an idea about how quickly the events are coming in from this wheel. Thanks, Simon. ------=_20121024002616_92581 Content-Type: application/x-gzip; name="SDL_missing_events2.txt.gz" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="SDL_missing_events2.txt.gz" H4sICJGzgFAAA1NETF9taXNzaW5nX2V2ZW50czIudHh0AK1aS28cNww+r3+FDgG8BjK2SL2D9hCg 7aHIqbm1yMGOp/W2jm1k14u66I8vtUbtSg41ZNBLEGK433D4/Cj51bzfzdudObuc92ebm7v73dm8 n292zvxtfvs835lpNscfby9n8wuGD8dH03T0fX3+xuw2n2YDLtgIYMGflhBTCq/N7uFuNs6s315s b6/vd/PJa3P4PZr1z/T//fn1PQm+rFbfTJP5dfOZ3r6d5xtz8WDef/eOh88pFim8yyxOtCmiFAcH OKjBsTyOV+CA43Fiik6KYwOPQ35OQhwohcVJVh4vKMjjkJ+laQU58jgKP0Pm40XeiV6KExOPQ36O YhxgcbIinyHw+ZMV+Qyej1cmP1spjvM8TlT4x/HxyuTnLMVB/ruKTUn8XcDXRdH4Gfh8Lpp8HvSN EhU4lu+HRZPPlvmucGqtlfcx4PpYxdH42TL+IRz4n+wBlT28f0ATdy5eFUdTXwCP4/r6vJ3WZo3Z HAjD9oR/U04JxG9iOgLhoGaiANN5Kw6mJI4oN7krjs9W7EGOSVQcIk7iiDo+MzDLCRh4ZqIQjrOK iRt4/zhUVE7g/eM8zUrxpOTzx2kyPg1wNJ0ufzVOMOuf/nqmbANHe03ACt+iFnA6g5CZcRVI0+sK X6kLOL1BfGl4Lye1OGi+CzidQTAIWSggZZE46IkLOK1BQ1dnOa1FHBg0xukMynwyBkW3R47/LeN0 BqWBQYpFBB1fHAs4nUGRYaQVyCsMCmH1OMJ3V5ut2V7d3l9fmqvz/Wwu6jg/DPbHRR+Pv/aNneme b+khKuoIuG2+AqnSDfnoRk3vg0Fl13MBuUWWH8NR4+wywBkfDLQ4eYCTFc048Q6qBwODhazFGaT/ wsFAixP4jlUPBsT2+AGOxs+DlCayM6KnHQ4fr3owIJ9V/AJUDwbktcr3vaxqHgN7NL2DH3hZ0zn4 qBerIHFsUdDaM9wBOufwMDFbcS6zLgba2OShYtkS7U7ZyzsYD6NKQLbFA3pFgQJboICaBOQLi1bC lOXslvePsxnEDMfx/nEaP3s+l53PThx2vqHCwr4mbfDgNNkceD97TalH3s8ecxich3QNbIDjFR2M H+zgNX7OfF14zT5b+HjpGDvPoKAybbFBACzVAB3v5Q6RK5CO9+JqtY7/HrCZ40+b7Xa+PDbfGktZ nUqJ/KkbLNyXvaDYj9vBD4f7uPdL93GEryPM/C5AG45m9A3qkwhzkn9xHABFBSOENAAa3z301InP ZBVnRsvXFpHm0Vlsf4AxsEjDmtn7zwqkcTZ7IVuBNAmP/DkqZJWzPUsxQcWcDxt6LcF3L87YwT2d sU/T0dGr07N6Z3/45/fbh+1u8/EPopb06O2ftNsfVOsNu2lkl1sZe9m2Mr20kW1oZCilk7GVc+zk Fh9i6mRo5dC+n6ZmKzvfyR0+dvrQ2Qudfd33gs2d3On3/rD97/vn/e87fKDv//Epmua8PsLH3HhD ax71NrM+PPMlWnfC62KOrkh1ow1iXVdKkOoiZDGuBZTiQg5iP1CGJZDqBqR8EeoSL/VSXeuormS6 tPZLTYiJskemSuRXagCVaBSqJrEHJsAijcKENkozYcIszvLJRapuoa4vVqwbPIhtqH8eJdWNUOQ2 KHA19mr84CnIrW7TmbtO5zs5dJ05dnLqJw10k8l3kwvGk62ffK7tzDTRWzmEl53ZPXdb91yKBb/g pidV8r5UNWOIQlUaJE6s6zyIdWP4T9Es6Na/1hHqIvVlKW47chZ0m1G2oJsBpTY4WyJIdSvha3WJ lf0DbAps32QpAAA= ------=_20121024002616_92581--