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 474B7CCA473 for ; Fri, 24 Jun 2022 14:27:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232222AbiFXO1C (ORCPT ); Fri, 24 Jun 2022 10:27:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231772AbiFXO1A (ORCPT ); Fri, 24 Jun 2022 10:27:00 -0400 Received: from netrider.rowland.org (netrider.rowland.org [192.131.102.5]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 62FED4ECE7 for ; Fri, 24 Jun 2022 07:26:59 -0700 (PDT) Received: (qmail 33925 invoked by uid 1000); 24 Jun 2022 10:26:58 -0400 Date: Fri, 24 Jun 2022 10:26:58 -0400 From: Alan Stern To: Neal Liu Cc: Felipe Balbi , Greg Kroah-Hartman , Roger Quadros , Miaohe Lin , Wesley Cheng , "Eric W . Biederman" , Matthew Wilcox , Nikita Yushchenko , Cai Huoqing , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, BMC-SW@aspeedtech.com Subject: Re: [PATCH v2] usb: gadget: f_mass_storage: Make CD-ROM emulation works with Windows OS Message-ID: References: <20220624021916.318067-1-neal_liu@aspeedtech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220624021916.318067-1-neal_liu@aspeedtech.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 24, 2022 at 10:19:16AM +0800, Neal Liu wrote: > Add read TOC with format 1 to support CD-ROM emulation with > Windows OS. > This patch is tested on Windows OS Server 2019. > > Signed-off-by: Neal Liu > --- > drivers/usb/gadget/function/f_mass_storage.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c > index 3a77bca0ebe1..9edf76c22605 100644 > --- a/drivers/usb/gadget/function/f_mass_storage.c > +++ b/drivers/usb/gadget/function/f_mass_storage.c > @@ -1209,7 +1209,8 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh) > > switch (format) { > case 0: > - /* Formatted TOC */ > + case 1: > + /* Formatted TOC, Session info */ This comment is a little misleading. 0 is formatted TOC, and 1 is multi-session info. The way you wrote it, it looks like the comment applies to both formats. Do it like this: case 0: /* Formatted TOC */ case 1: /* Multi-session info */ > len = 4 + 2*8; /* 4 byte header + 2 descriptors */ > memset(buf, 0, len); > buf[1] = len - 2; /* TOC Length excludes length field */ It looks like you ignored one of the problems I pointed out in my earlier email: > When format is 1, the driver is supposed to ignore the start_track > value. Your patch does not do this. Please fix this. Alan Stern > @@ -1250,7 +1251,7 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh) > return len; > > default: > - /* Multi-session, PMA, ATIP, CD-TEXT not supported/required */ > + /* PMA, ATIP, CD-TEXT not supported/required */ > curlun->sense_data = SS_INVALID_FIELD_IN_CDB; > return -EINVAL; > } > -- > 2.25.1 >