Hi Christian,
Thank you for the patch.
On Mon, Jan 23, 2023 at 01:37:56PM +0100, Christian König wrote:
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@amd.com
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);
Could we avoid having to call this explicitly in drivers, possibly using devres in dma_heap_create_device_link() ?
#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"))
I don't think this is the right device. A UVC device is usually a composite USB device with an audio (UAC) function in addition to UVC, and that may require a different heap (at least conceptually). Wouldn't the video_device be a better candidate to expose the link ? This would create a race condition though, as the link will be created after userspace gets notified of the device being available.
goto error;- /* Register the V4L2 device. */ if (v4l2_device_register(&intf->dev, &dev->vdev) < 0) goto error;