Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753031AbcD2L2L (ORCPT ); Fri, 29 Apr 2016 07:28:11 -0400 Received: from nat-hk.nvidia.com ([203.18.50.4]:54029 "EHLO hkmmgate101.nvidia.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752269AbcD2L2I convert rfc822-to-8bit (ORCPT ); Fri, 29 Apr 2016 07:28:08 -0400 X-PGP-Universal: processed; by hkpgpgate101.nvidia.com on Fri, 29 Apr 2016 04:28:05 -0700 Subject: Re: [PATCH] usb: gadget: f_fs: Fix kernel panic for SuperSpeed To: Felipe Balbi References: <1461321780-3226-1-git-send-email-jilin@nvidia.com> <87bn51uagb.fsf@intel.com> <571E0058.6020007@nvidia.com> <87r3dtrj7b.fsf@intel.com> <571F2BA3.6040209@nvidia.com> <871t5plya5.fsf@intel.com> CC: , From: Jim Lin Message-ID: <57234522.9000607@nvidia.com> Date: Fri, 29 Apr 2016 19:27:30 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <871t5plya5.fsf@intel.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.19.108.174] X-ClientProxiedBy: DRBGMAIL101.nvidia.com (10.18.16.20) To HKMAIL103.nvidia.com (10.18.16.12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1818 Lines: 58 On 2016年04月28日 20:21, Felipe Balbi wrote: >> >> I also attach git log of system/core/adb/usb_linux_client.cpp of Android >> N for your reference. >> " >> Author: Badhri Jagan Sridharan >> Date: Mon Oct 5 13:04:03 2015 -0700 >> >> adbd: Add os descriptor support for adb. >> >> Eventhough windows does not rely on extended os >> descriptor for adbd, when android usb device is >> configures as a composite device such as mtp+adb, >> windows discards the extended os descriptor even >> if one of the USB function fails to send >> the extended compat descriptor. This results in automatic >> install of MTP driverto fail when Android device is in >> "File Transfer" mode with adb enabled. >> >> https://msdn.microsoft.com/en-us/library/windows/hardware/gg463179.aspx >> " > Okay, cool. Can you check that you're limitting your controller's speed > to high-speed ? > Let's focus on original patch. Could you help to explain why we need below d->Reserved1 checking? Now the question is that https://msdn.microsoft.com/en-us/library/windows/hardware/gg463179.aspx Page 7 of OS_Desc_CompatID.doc defines reserved field to be 1 and below code will think that os_desc is invalid because d->Reserved1 is 1. In f_fs.c " static int __ffs_data_do_os_desc(enum ffs_os_desc_type type, struct usb_os_desc_header *h, void *data, unsigned len, void *priv) { struct ffs_data *ffs = priv; u8 length; ENTER(); switch (type) { case FFS_OS_DESC_EXT_COMPAT: { struct usb_ext_compat_desc *d = data; int i; if (len < sizeof(*d) || d->bFirstInterfaceNumber >= ffs->interfaces_count || d->Reserved1) return -EINVAL; " --nvpublic