From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELvQOwrjflzVzky5zcd6+K7fTrVzk3IrwZ2RRjl4nBjy/v5m5U17bCOXfQj6cZ38Mv27fu1j ARC-Seal: i=1; a=rsa-sha256; t=1520004433; cv=none; d=google.com; s=arc-20160816; b=nj0Q7PkKb/9DSLxKdA/XcvB1aKJ353BkAnHgcc0OG0mKrQzE7VZ6VZusy087PBMtSe HYbKhmsJPe/7neKsENyFV3/NX5F0b344a1kmYqwSrvbA1TVRn2s8kHX2NYnFm/chSN3l U96iFBNqYSTFq0TmjDcPG8F9oXAQ40cwwog5uCuRAqNzID3L8MFb5/c2a5Z8doR8yXW4 rpivqafaMmCKJzRxv99vGCIn55lOSKXmGyEVbr021SFSR6nqIUdyw56lhqCbIb82tJKD NvJVe6F4zWBMiQjB8ufDhV0/t4GhTj6x08p8BPbFyYteU+lyc3OK0qL5YsnXfntxozUQ pQMQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:dkim-signature :arc-authentication-results; bh=sk0bt7ZUTcBzu6Vi3CkULc8ap11D3qRvKIIEt3VZ00Q=; b=YIjxTGhfuG30wKijvSjLrW0LD+ophvST5bd/shDgmBFMzuVIn0rOslbrg0SlumJHwP C7vnUH0dp0JK+1b/TG0zSGKAXrEVX6pqRE8umrmBwyqKdOhHbqzxYRS7ym96VWg0EZFY je4JXl0QUMn19ThnA2fMgJUJahMGmx2EbHjvh/CUkG75xsAf20IuF61/INaz85Q5zrci 5iYhvzp4p+sarMME8BSVE3mcieB+3Y23O6q9wigj5XRAZC1TG1bNmqE3N03KDjtiCRDL Y9ke7lyNKNJpATdGPr0XfWTxT0iV58ISRaEUpCmEFCt1b2l7tWYd9mzzd5vU+EA9TVuW /ZRg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=i1eGBB4W; spf=pass (google.com: domain of b-liu@ti.com designates 198.47.27.77 as permitted sender) smtp.mailfrom=b-liu@ti.com; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Authentication-Results: mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=i1eGBB4W; spf=pass (google.com: domain of b-liu@ti.com designates 198.47.27.77 as permitted sender) smtp.mailfrom=b-liu@ti.com; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Date: Fri, 2 Mar 2018 09:27:12 -0600 From: Bin Liu To: Merlijn Wajer CC: Greg Kroah-Hartman , , , Pali =?iso-8859-1?Q?Roh=E1r?= , Ivaylo Dimitrov , Subject: Re: usb: musb: "(null)" in sysfs mode file after disabling a gadget (and at other times, system hangs) Message-ID: <20180302152712.GA22262@uda0271908> Mail-Followup-To: Bin Liu , Merlijn Wajer , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Pali =?iso-8859-1?Q?Roh=E1r?= , Ivaylo Dimitrov , linux-omap@vger.kernel.org References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1593781038730915565?= X-GMAIL-MSGID: =?utf-8?q?1593840168787670673?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hi, On Fri, Mar 02, 2018 at 12:47:07AM +0100, Merlijn Wajer wrote: > Hi, > > I found that the "mode" file in musb sys node will return "(null)" when > one would expect it show b_idle. > > Wrong /mode file: > > [Fresh boot, cable not connected yet] > root@n900devuan:~# modprobe g_nokia > [Insert cable connected to PC] > root@n900devuan:~# cat > /sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto/mode > b_peripheral > [Remove cable connected to PC] > root@n900devuan:~# cat > /sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto/mode > b_idle > root@n900devuan:~# rmmod g_nokia > root@n900devuan:~# cat > /sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto/mode > (null) I can reproduce this on AM335x EVM, > [Insert cable connected to PC] > root@n900devuan:~# cat > /sys/devices/platform/68000000.ocp/480ab000.usb_otg_hs/musb-hdrc.0.auto/mode > b_idle but not this, I still get (null). g_nokia is not loaded here, right? > > I would expect it to state "b_idle" instead of "(null)". Actually, I'd like to see (null) whenever a gadget driver is not loaded, which indicates a gadget is not bound to the udc. Regards, -Bin.