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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86971C433F5 for ; Tue, 5 Oct 2021 11:37:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F71E610A2 for ; Tue, 5 Oct 2021 11:37:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234229AbhJELjj (ORCPT ); Tue, 5 Oct 2021 07:39:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:54304 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234070AbhJELji (ORCPT ); Tue, 5 Oct 2021 07:39:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3DF7461371; Tue, 5 Oct 2021 11:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633433868; bh=t9DvBZnt4NNB7a0hcVaRvNBVvNKcckqWJY4ipVgovO0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lHE1QeNmznD6bnVbAVT3PwtWG3F6j6eAQyCCOUhGsVyLQyT/6RQWjOkdXYES9IjiY hAVEW3AYeZStlx+Oz/2XuJ2Q3y7LKExTe+5+mafaKUWIlWkkgfGtHCKytRNFBpkF4S DLAPqKDgZoDe3QeKwAJFPsiTe2UBjroyH0FS/CLo= Date: Tue, 5 Oct 2021 13:37:46 +0200 From: Greg KH To: Felipe Balbi Cc: Laurent Pinchart , Michael Grzeschik , linux-usb@vger.kernel.org, hverkuil@xs4all.nl, m.tretter@pengutronix.de, linux-media@vger.kernel.org Subject: Re: [RESEND PATCH v4] usb: gadget: uvc: fix multiple opens Message-ID: References: <87pn261h4c.fsf@kernel.org> <20211003201355.24081-1-m.grzeschik@pengutronix.de> <87a6jnzq64.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a6jnzq64.fsf@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Tue, Oct 05, 2021 at 02:06:22PM +0300, Felipe Balbi wrote: > > Greg KH writes: > > > On Tue, Oct 05, 2021 at 02:53:48AM +0300, Laurent Pinchart wrote: > >> Hi Michael, > >> > >> Thank you for resending this. > >> > >> On Sun, Oct 03, 2021 at 10:13:55PM +0200, Michael Grzeschik wrote: > >> > From: Thomas Haemmerle > >> > > >> > Currently, the UVC function is activated when open on the corresponding > >> > v4l2 device is called. > >> > On another open the activation of the function fails since the > >> > deactivation counter in `usb_function_activate` equals 0. However the > >> > error is not returned to userspace since the open of the v4l2 device is > >> > successful. > >> > > >> > On a close the function is deactivated (since deactivation counter still > >> > equals 0) and the video is disabled in `uvc_v4l2_release`, although the > >> > UVC application potentially is streaming. > >> > > >> > Move activation of UVC function to subscription on UVC_EVENT_SETUP > >> > because there we can guarantee for a userspace application utilizing > >> > UVC. > >> > Block subscription on UVC_EVENT_SETUP while another application already > >> > is subscribed to it, indicated by `bool func_connected` in > >> > `struct uvc_device`. > >> > Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` > >> > to tag it as the handle used by the userspace UVC application. > >> > >> Reflowing the paragraph would be nice (this could be done when applying > >> the patch, or not at all). > >> > >> > With this a process is able to check capabilities of the v4l2 device > >> > without deactivating the function for the actual UVC application. > >> > > >> > Reviewed-By: Michael Tretter > >> > Signed-off-by: Thomas Haemmerle > >> > Signed-off-by: Michael Tretter > >> > Signed-off-by: Michael Grzeschik > >> > >> Reviewed-by: Laurent Pinchart > >> > >> Felipe, please let me know if you want me to take this in my tree and > >> issue a pull request, otherwise I'll assume you'll pick it up. > > > > I'll pick it up now, thanks. > > I guess it's too late for an Ack. FWIW: > > Acked-by: Felipe Balbi Nope, not too late, just added, thanks! greg k-h