From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90DDDC28CF5 for ; Wed, 26 Jan 2022 16:09:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238708AbiAZQJZ (ORCPT ); Wed, 26 Jan 2022 11:09:25 -0500 Received: from netrider.rowland.org ([192.131.102.5]:56867 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S235786AbiAZQJY (ORCPT ); Wed, 26 Jan 2022 11:09:24 -0500 Received: (qmail 141771 invoked by uid 1000); 26 Jan 2022 11:09:23 -0500 Date: Wed, 26 Jan 2022 11:09:23 -0500 From: Alan Stern To: Michael Grzeschik Cc: kieran.bingham@ideasonboard.com, linux-usb@vger.kernel.org, balbi@kernel.org, paul.elder@ideasonboard.com, laurent.pinchart@ideasonboard.com, kernel@pengutronix.de, nicolas@ndufresne.ca Subject: Re: [PATCH] dummy_hcd: add isoc support Message-ID: References: <164154749753.1224575.16682991529695492259@Monstersaurus> <20220126132249.2133168-1-m.grzeschik@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220126132249.2133168-1-m.grzeschik@pengutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Jan 26, 2022 at 02:22:49PM +0100, Michael Grzeschik wrote: > With this patch, the dummy_hcd gains first support for isoc transfers. > It will complete the whole urb with all packages. "packets", not "packages". > Even if the gadget > side did not enqueue any request, the urb will be handled. > > Signed-off-by: Michael Grzeschik I don't like this idea. If support for isochronous transfers is added, it should be done correctly. That is, the implementation should support scheduling of transfers, periodic bandwidth reservation, high-bandwidth transfers, and so on. The whole point of dummy-hcd is to emulate a real host controller as closely as possible. Real isochronous transfers do not complete all at once. Alan Stern