From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from ns1.tyldum.com ([91.189.178.231]:42934 "EHLO ns1.tyldum.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753453Ab1LMQ4I (ORCPT ); Tue, 13 Dec 2011 11:56:08 -0500 Received: from tyldum.com (unknown [192.168.168.50]) by ns1.tyldum.com (Postfix) with ESMTP for ; Tue, 13 Dec 2011 17:56:02 +0100 (CET) Received: from [192.168.168.92] (unknown [192.168.168.92]) by tyldum.com (Postfix) with ESMTP id 9B17428377 for ; Tue, 13 Dec 2011 17:56:00 +0100 (CET) Message-ID: <4EE7839A.6040507@tyldum.com> Date: Tue, 13 Dec 2011 17:55:54 +0100 From: Vidar Tyldum MIME-Version: 1.0 To: linux-media@vger.kernel.org Subject: Re: Multiple Mantis devices gives me glitches References: <4EE682B3.4090301@tyldum.com> In-Reply-To: <4EE682B3.4090301@tyldum.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: (sorry for breaking the threading, the reply came faster than my subscription to the list :) >>From Ninja , > Hi, I noticed some SMP problems with the mantis driver as well (see my > post "Mantis CAM not SMP safe / Activating CAM on Technisat Skystar HD2 > (DVB-S2)"). One workaround for me is to limit the CPU to one core (to be > sure disable the hyperthreading cores as well). That can be done via BIOS > *or* adding maxcpus=1 as kernel parameter *or* you can disable the cores > one by one via "|echo 0 > /sys/devices/system/cpu/cpuX/online|" where X > is the core to disable. Since you need to be root for this, I did "sudo > su" first. But of course our problems might be completely unrelated and > limiting to one core won't change a thing ;) > > Manuel I doubt I'll revert back to the stock mantis module to test right now, but your suggestion and observations might certainly be of interest. If/when Ubuntu releases a new kernel which overwrites my current driver I will give it a go. However, instead of disabling SMP completely I hope adjusting IRQ affinity could be sufficient: http://kernel.org/doc/Documentation/IRQ-affinity.txt Couple this with increased PCI latency might work, however with three devices connected I think the only solution is to reduce the number of interrupts (though I am by no means any expert on this subject). -- Vidar Tyldum vidar@tyldum.com PGP: 0x3110AA98