Expose an indicator to let userspace know from which dma_heap to allocate for buffers of this device. Signed-off-by: Christian König <christian.koenig@xxxxxxx> --- drivers/media/usb/uvc/uvc_driver.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index e4bcb5011360..b247026b68c5 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -7,6 +7,7 @@ */ #include <linux/atomic.h> +#include <linux/dma-heap.h> #include <linux/gpio/consumer.h> #include <linux/kernel.h> #include <linux/list.h> @@ -1909,6 +1910,8 @@ static void uvc_unregister_video(struct uvc_device *dev) if (dev->vdev.dev) v4l2_device_unregister(&dev->vdev); + dma_heap_remove_device_link(&dev->udev->dev); + #ifdef CONFIG_MEDIA_CONTROLLER if (media_devnode_is_registered(dev->mdev.devnode)) media_device_unregister(&dev->mdev); @@ -2181,6 +2184,14 @@ static int uvc_probe(struct usb_interface *intf, dev->uvc_version >> 8, dev->uvc_version & 0xff); } + /* + * UVC exports DMA-buf buffers with dirty CPU caches. For compatibility + * with device which can't snoop the CPU cache it's best practice to + * allocate DMA-bufs from the system DMA-heap. + */ + if (dma_heap_create_device_link(&dev->udev->dev, "system")) + goto error; + /* Register the V4L2 device. */ if (v4l2_device_register(&intf->dev, &dev->vdev) < 0) goto error; -- 2.34.1
