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[34.150.221.228]) by smtp.gmail.com with ESMTPSA id ct2-20020a056214178200b0065b0d9b4ee7sm4199409qvb.20.2023.11.21.11.53.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Nov 2023 11:53:52 -0800 (PST) From: Ricardo Ribalda Date: Tue, 21 Nov 2023 19:53:49 +0000 Subject: [PATCH v3 2/3] media: uvcvideo: Do not halt the device after disconnect MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20231121-guenter-mini-v3-2-d8a5eae2312b@chromium.org> References: <20231121-guenter-mini-v3-0-d8a5eae2312b@chromium.org> In-Reply-To: <20231121-guenter-mini-v3-0-d8a5eae2312b@chromium.org> To: Mauro Carvalho Chehab Cc: Guenter Roeck , Tomasz Figa , Laurent Pinchart , Alan Stern , Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Paul , Ricardo Ribalda , Sakari Ailus X-Mailer: b4 0.12.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org usb drivers should not call to any usb_() function after the .disconnect() callback has been triggered. If the camera is streaming, the uvc driver will call usb_set_interface or usb_clear_halt once the device is being released. Let's fix this issue. This is probably not the only driver affected with this kind of bug, but until there is a better way to do it in the core this is the way to solve this issue. When/if a different mechanism is implemented in the core to solve the lifetime of devices we will adopt it in uvc. Trace: [ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter [ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit [ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter [ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_stream= ing enter [ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_stream= ing exit [ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit [ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter Signed-off-by: Ricardo Ribalda --- drivers/media/usb/uvc/uvc_driver.c | 2 ++ drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++----------= ---- drivers/media/usb/uvc/uvcvideo.h | 2 ++ 3 files changed, 32 insertions(+), 17 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc= _driver.c index 08fcd2ffa727..413c32867617 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf) return; =20 uvc_unregister_video(dev); + /* Barrier needed to synchronize with uvc_video_stop_streaming(). */ + smp_store_release(&dev->disconnected, true); kref_put(&dev->ref, uvc_delete); } =20 diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_= video.c index 28dde08ec6c5..032b44e45b22 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming = *stream) return ret; } =20 -void uvc_video_stop_streaming(struct uvc_streaming *stream) +static void uvc_video_halt(struct uvc_streaming *stream) { - uvc_video_stop_transfer(stream, 1); + unsigned int epnum; + unsigned int pipe; + unsigned int dir; =20 if (stream->intf->num_altsetting > 1) { usb_set_interface(stream->dev->udev, stream->intfnum, 0); - } else { - /* - * UVC doesn't specify how to inform a bulk-based device - * when the video stream is stopped. Windows sends a - * CLEAR_FEATURE(HALT) request to the video streaming - * bulk endpoint, mimic the same behaviour. - */ - unsigned int epnum =3D stream->header.bEndpointAddress - & USB_ENDPOINT_NUMBER_MASK; - unsigned int dir =3D stream->header.bEndpointAddress - & USB_ENDPOINT_DIR_MASK; - unsigned int pipe; - - pipe =3D usb_sndbulkpipe(stream->dev->udev, epnum) | dir; - usb_clear_halt(stream->dev->udev, pipe); + return; } =20 + /* + * UVC doesn't specify how to inform a bulk-based device + * when the video stream is stopped. Windows sends a + * CLEAR_FEATURE(HALT) request to the video streaming + * bulk endpoint, mimic the same behaviour. + */ + epnum =3D stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK; + dir =3D stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK; + pipe =3D usb_sndbulkpipe(stream->dev->udev, epnum) | dir; + usb_clear_halt(stream->dev->udev, pipe); +} + +void uvc_video_stop_streaming(struct uvc_streaming *stream) +{ + uvc_video_stop_transfer(stream, 1); + + /* + * Barrier needed to synchronize with uvc_disconnect(). + * We cannot call usb_* functions on a disconnected USB device. + */ + if (!smp_load_acquire(&stream->dev->disconnected)) + uvc_video_halt(stream); + uvc_video_clock_cleanup(stream); } diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvi= deo.h index 6fb0a78b1b00..4318ce8e31db 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -559,6 +559,8 @@ struct uvc_device { unsigned int users; atomic_t nmappings; =20 + bool disconnected; + /* Video control interface */ #ifdef CONFIG_MEDIA_CONTROLLER struct media_device mdev; --=20 2.43.0.rc1.413.gea7ed67945-goog