Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753755AbZKVK6t (ORCPT ); Sun, 22 Nov 2009 05:58:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751568AbZKVK6s (ORCPT ); Sun, 22 Nov 2009 05:58:48 -0500 Received: from proxima.lp0.eu ([81.2.80.65]:35358 "EHLO proxima.lp0.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751143AbZKVK6r (ORCPT ); Sun, 22 Nov 2009 05:58:47 -0500 Message-ID: <4B09196D.7040107@simon.arlott.org.uk> Date: Sun, 22 Nov 2009 10:58:53 +0000 From: Simon Arlott User-Agent: Thunderbird 2.0.0.23 (X11/20090927) MIME-Version: 1.0 To: Alan Stern CC: USB list , Kernel development list Subject: Re: cxacru usb_bulk_msg() firmware upload 36x slower with OHCI vs. UHCI References: In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1350 Lines: 30 On 18/11/09 22:25, Alan Stern wrote: > On Wed, 18 Nov 2009, Simon Arlott wrote: >> > What happens with other sorts of devices, such as a USB flash drive? >> >> I can write a 10MB file to an USB flash drive over OHCI, and umount+sync >> takes around 13 seconds. > > Yes, that's about right. It leads me to wonder if something funny is > going on with the device, or least with the firmware-loading part of > it. Odd that it works differently with UHCI and OHCI, though. There > shouldn't be any differences visible to the device. You don't have > anything else attached to the same bus, do you? Yes, but not in use and I could disconnect everything to test it. core/hcd.c has an interesting comment in usb_hcd_check_unlink_urb(): /* The USB 2.0 spec says 256 ms. This is close enough and won't * exceed that limit if HZ is 100. The math is more clunky than * maybe expected, this is to make sure that all timers for USB devices * fire at the same time to give the CPU a break inbetween */ I'll try increasing the frequency of this timer too. -- Simon Arlott -- 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/