Re: [virtio-dev] Re: [PATCH v2 2/9] ALSA: virtio: add virtio sound driver

On Tue, 02 Feb 2021 00:18:09 +0100, Anton Yakovlev wrote:

...

...

+/**

• • virtsnd_reset_fn() - Kernel worker's function to reset the device.
• • @work: Reset device work.
• • Context: Process context.
• */

+static void virtsnd_reset_fn(struct work_struct *work) +{

• struct virtio_snd *snd =
  

•         container_of(work, struct virtio_snd, reset_work);
  

• struct virtio_device *vdev = snd->vdev;
  

• struct device *dev = &vdev->dev;
  

• int rc;
  

• dev_info(dev, "sound device needs reset\n");
  

• /*
  

•  * It seems that the only way to properly reset the device is to
  

remove

•  * and re-create the ALSA sound card device.
  

•  *
  

•  * Also resetting the device involves a number of steps with
  

setting the

•  * status bits described in the virtio specification. And the
  

easiest

•  * way to get everything right is to use the virtio bus interface.
  

•  */
  

• rc = dev->bus->remove(dev);
  

• if (rc)
  

•         dev_warn(dev, "bus->remove() failed: %d", rc);
  

• rc = dev->bus->probe(dev);
  

• if (rc)
  

•         dev_err(dev, "bus->probe() failed: %d", rc);
  

This looks very suspicious to me. Wondering what ALSA maintainers

will say

...

to this.

I'm also wondering what the virtio people have to say. This part is a purely virtio specific thing. And since none of the existing virtio drivers processes the request to reset the device, it is not clear what is the best way to proceed here. For this reason, the most straightforward and simple solution was chosen.

What is this "reset" actually supposed to do? Reconfguring everything, or changing only certain parameters, devices, whatever?

thanks,

Takashi