Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752582Ab1F3SBI (ORCPT ); Thu, 30 Jun 2011 14:01:08 -0400 Received: from mga09.intel.com ([134.134.136.24]:11452 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751027Ab1F3SBF (ORCPT ); Thu, 30 Jun 2011 14:01:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.65,453,1304319600"; d="scan'208";a="20227554" Date: Thu, 30 Jun 2011 11:01:01 -0700 From: Sarah Sharp To: Kirill Smelkov Cc: Alan Stern , matt mooney , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-uvc-devel@lists.berlios.de, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/2] USB: EHCI: Allow users to override 80% max periodic bandwidth Message-ID: <20110630180101.GB7979@xanatos> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 37 On Fri, Jun 24, 2011 at 08:48:06PM +0400, Kirill Smelkov wrote: > > Changes since v1: > > > - dropped RFC status as "this seems like the sort of feature somebody might > reasonably want to use -- if they know exactly what they're doing"; > > - new preparatory patch (1/2) which moves already-in-there sysfs code into > ehci-sysfs.c; > > - moved uframe_periodic_max parameter from module option to sysfs attribute, > so that it can be set per controller and at runtime, added validity checks; > > - clarified a bit bandwith analysis for 96% max periodic setup as noticed by > Alan Stern; > > - clarified patch description saying that set in stone 80% max periodic is > specified by USB 2.0; Have you tested this patch by maxing out this bandwidth on various types of host controllers? It's entirely possible that you'll run into vendor-specific bugs if you try to pack the schedule with isochronous transfers. I don't think any hardware designer would seriously test or validate their hardware with a schedule that is basically a violation of the USB bus spec (more than 80% for periodic transfers). But if Alan is fine with giving users a way to shoot themselves in the foot, and it's disabled by default, then I don't particularly mind this patch. Sarah Sharp -- 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/