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 A4D7DC10F1B for ; Wed, 28 Dec 2022 02:09:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232627AbiL1CJi (ORCPT ); Tue, 27 Dec 2022 21:09:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232621AbiL1CJd (ORCPT ); Tue, 27 Dec 2022 21:09:33 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67FFEBE11 for ; Tue, 27 Dec 2022 18:09:32 -0800 (PST) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 970C925B; Wed, 28 Dec 2022 03:09:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1672193370; bh=fEyXzGizlZD7fXSpjsuJsiZRyfszhpF9+JLhw6oTE8Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dv88RnkTz5yoImhVLPiyz47KzHcsCb1HPJQ/FlXlur8VhLYcBHhekOoTabWh8EDo1 zYKv4ZnPpy+k8jTr9ubo/dyNnJNkU90EBGv1lrkD2Uxn3pYZWs78mAHBQwNLDkz/FV oXk7cWlNbfLEL1dKsOStvZfprRbwIXgpa/kJ0Zw4= Date: Wed, 28 Dec 2022 04:09:27 +0200 From: Laurent Pinchart To: Daniel Scally Cc: linux-usb@vger.kernel.org, gregkh@linuxfoundation.org, mgr@pengutronix.de, kieran.bingham@ideasonboard.com Subject: Re: [PATCH 3/3] usb: gadget: uvc: Allow disabling of interrupt endpoint Message-ID: References: <20221205143758.1096914-1-dan.scally@ideasonboard.com> <20221205143758.1096914-4-dan.scally@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221205143758.1096914-4-dan.scally@ideasonboard.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hi Dan, Thank you for the patch. On Mon, Dec 05, 2022 at 02:37:58PM +0000, Daniel Scally wrote: > The f_uvc code includes an interrupt endpoint against the VideoControl > interface. According to section 2.4.2 of the UVC specification however > this endpoint is optional in at least some cases: > > "This endpoint is optional, but may be mandatory under certain > conditions" > > The conditions enumerated are whether... > > 1. The device supports hardware triggers > 2. The device implements any AutoUpdate controls > 3. The device implements any Asynchronous controls > > As all of those things are implementation dependent, this endpoint > might be unnecessary for some users. Check whether the user has > requested it be disable via configfs and don't proceed with its s/disable/disabled/ > instantiation if so. > > Signed-off-by: Daniel Scally > --- > drivers/usb/gadget/function/f_uvc.c | 42 ++++++++++++++++++----------- > drivers/usb/gadget/function/uvc.h | 1 + > 2 files changed, 27 insertions(+), 16 deletions(-) > > diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c > index 49b7231742d6..76ec84d3a5fd 100644 > --- a/drivers/usb/gadget/function/f_uvc.c > +++ b/drivers/usb/gadget/function/f_uvc.c > @@ -79,7 +79,7 @@ static struct usb_interface_descriptor uvc_control_intf = { > .bDescriptorType = USB_DT_INTERFACE, > .bInterfaceNumber = UVC_INTF_VIDEO_CONTROL, > .bAlternateSetting = 0, > - .bNumEndpoints = 1, > + .bNumEndpoints = 0, > .bInterfaceClass = USB_CLASS_VIDEO, > .bInterfaceSubClass = UVC_SC_VIDEOCONTROL, > .bInterfaceProtocol = 0x00, > @@ -290,14 +290,16 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt) > if (alt) > return -EINVAL; > > - uvcg_info(f, "reset UVC interrupt endpoint\n"); > - usb_ep_disable(uvc->interrupt_ep); > + if (!uvc->disable_interrupt_ep) { > + uvcg_info(f, "reset UVC interrupt endpoint\n"); > + usb_ep_disable(uvc->interrupt_ep); > > - if (!uvc->interrupt_ep->desc) > - if (config_ep_by_speed(cdev->gadget, f, uvc->interrupt_ep)) > - return -EINVAL; > + if (!uvc->interrupt_ep->desc) > + if (config_ep_by_speed(cdev->gadget, f, uvc->interrupt_ep)) Line wrap would be nice. if (config_ep_by_speed(cdev->gadget, f, uvc->interrupt_ep)) > + return -EINVAL; > > - usb_ep_enable(uvc->interrupt_ep); > + usb_ep_enable(uvc->interrupt_ep); > + } > > if (uvc->state == UVC_STATE_DISCONNECTED) { > memset(&v4l2_event, 0, sizeof(v4l2_event)); > @@ -375,7 +377,8 @@ uvc_function_disable(struct usb_function *f) > uvc->state = UVC_STATE_DISCONNECTED; > > usb_ep_disable(uvc->video.ep); > - usb_ep_disable(uvc->interrupt_ep); > + if (!uvc->disable_interrupt_ep) > + usb_ep_disable(uvc->interrupt_ep); > } > > /* -------------------------------------------------------------------------- > @@ -523,8 +526,10 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed) > control_size = 0; > streaming_size = 0; > bytes = uvc_iad.bLength + uvc_control_intf.bLength > - + uvc_interrupt_ep.bLength + uvc_control_cs_ep.bLength > - + uvc_streaming_intf_alt0.bLength; > + + uvc_control_cs_ep.bLength + uvc_streaming_intf_alt0.bLength; Wrong indentation. > + > + if (!uvc->disable_interrupt_ep) > + bytes += uvc_interrupt_ep.bLength; > > if (speed == USB_SPEED_SUPER) { > bytes += uvc_ss_control_comp.bLength; > @@ -569,7 +574,8 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed) > uvc_control_header->bInCollection = 1; > uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf; > > - UVC_COPY_DESCRIPTOR(mem, dst, &uvc_interrupt_ep); > + if (!uvc->disable_interrupt_ep) > + UVC_COPY_DESCRIPTOR(mem, dst, &uvc_interrupt_ep); > if (speed == USB_SPEED_SUPER) > UVC_COPY_DESCRIPTOR(mem, dst, &uvc_ss_control_comp); This is the companion descriptor for the interrupt endpoint, it should only be included if the interrupt endpoint is enabled. Same for uvc_control_cs_ep. > > @@ -656,12 +662,16 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f) > (opts->streaming_maxburst + 1)); > > /* Allocate endpoints. */ > - ep = usb_ep_autoconfig(cdev->gadget, &uvc_interrupt_ep); > - if (!ep) { > - uvcg_info(f, "Unable to allocate control EP\n"); > - goto error; > + if (!opts->disable_interrupt_ep) { > + ep = usb_ep_autoconfig(cdev->gadget, &uvc_interrupt_ep); > + if (!ep) { > + uvcg_info(f, "Unable to allocate interrupt EP\n"); > + goto error; > + } > + uvc->interrupt_ep = ep; > + uvc_control_intf.bNumEndpoints = 1; > } > - uvc->interrupt_ep = ep; > + uvc->disable_interrupt_ep = opts->disable_interrupt_ep; Given that you always test for !uvc->disable_interrupt_ep, how about naming this enable_interrupt_ep and switching the tests ? I think positive logic is more readable that double negation. I would then move this line up, in order to test uvc->enable_interrupt_ep instead of !opts->disable_interrupt_ep above. > > if (gadget_is_superspeed(c->cdev->gadget)) > ep = usb_ep_autoconfig_ss(cdev->gadget, &uvc_ss_streaming_ep, > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index 48b71e04c2b1..0d0ef9b90b1a 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -149,6 +149,7 @@ struct uvc_device { > struct usb_ep *interrupt_ep; > struct usb_request *control_req; > void *control_buf; > + bool disable_interrupt_ep; > > unsigned int streaming_intf; > -- Regards, Laurent Pinchart