Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265970AbUIVUvk (ORCPT ); Wed, 22 Sep 2004 16:51:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266116AbUIVUvk (ORCPT ); Wed, 22 Sep 2004 16:51:40 -0400 Received: from ida.rowland.org ([192.131.102.52]:55812 "HELO ida.rowland.org") by vger.kernel.org with SMTP id S265970AbUIVUvh (ORCPT ); Wed, 22 Sep 2004 16:51:37 -0400 Date: Wed, 22 Sep 2004 16:51:37 -0400 (EDT) From: Alan Stern X-X-Sender: stern@ida.rowland.org To: Florian Weimer cc: Hisaaki Shibata , USB users list , Kernel development list Subject: Re: Genesys and IEEE 1394 (was: Re: Genesys Logic and Kernel 2.4) In-Reply-To: <87d60eqcvu.fsf_-_@deneb.enyo.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1415 Lines: 40 On Wed, 22 Sep 2004, Florian Weimer wrote: > * Hisaaki Shibata: > > >> + /* According to the technical support people at Genesys Logic, > >> + * devices using their chips have problems transferring more > >> + * than 32 KB at a time. In practice people have found that > >> + * 64 KB works okay and that's what Windows does. But we'll > >> + * be conservative. > >> + */ > >> + if (ss->pusb_dev->descriptor.idVendor == USB_VENDOR_ID_GENESYS) > >> + ss->htmplt->max_sectors = 64; > > > > + ss->htmplt.max_sectors = 64; > > > >> + > > Christoph Biedl discovered that it's likely that a a similar > workaround is needed in the IEEE 1394 code: > > http://sourceforge.net/mailarchive/forum.php?thread_id=5128811&forum_id=5389 That change was not the important one. The important part of the patch was this: + /* Genesys Logic interface chips need a 100us delay between + * the command phase and the data phase */ + if (us->pusb_dev->descriptor.idVendor == USB_VENDOR_ID_GENESYS) + udelay(100); This is what affects the timing problem, by adding a 100-microsecond delay. Alan Stern - 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/