From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753470Ab1JMTHR (ORCPT ); Thu, 13 Oct 2011 15:07:17 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:35747 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751666Ab1JMTHQ (ORCPT ); Thu, 13 Oct 2011 15:07:16 -0400 Date: Thu, 13 Oct 2011 20:05:26 +0100 From: Alan Cox To: Alan Stern Cc: Markus Rechberger , Greg KH , USB list , LKML Subject: Re: [Patch] Increase USBFS Bulk Transfer size Message-ID: <20111013200526.74fcc87b@lxorguk.ukuu.org.uk> In-Reply-To: References: X-Mailer: Claws Mail 3.7.9 (GTK+ 2.24.4; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > For my part, I don't much mind raising the limit from 16 KB to 32 KB. > 48 KB may be unnecessary, especially since one of the devices doesn't > even work when the transfer buffer is that large. > > However it's just a work-around, not a real solution to the underlying > problem (whatever that problem turns out to be). Part of the reason > for keeping the limit low is that it shouldn't matter, since people > ought to be able to use a bunch of small transfers rather than one > large transfer. Apparently that justification doesn't work with these > webcams, although there's no known reason why it shouldn't. > > But I'm not the person in charge of these decisions... Well if the underlying solution is crap hardware with no work around its a bit hard to avoid. A more conservative approach would be to put the 'constant' in sysfs where it belongs so it can be adjusted and special cased. Alan