On 12/18/20 11:17 PM, Takashi Iwai wrote:
On Thu, 17 Dec 2020 17:45:05 +0100, Kai Vehmanen wrote:
Hey,
I gave a quick test spin and features seems to work as advertized. A few minor comments on the code. If Jaroslav you think this would be ok as an approach, I can give a more extensive test run on this.
The tree representation looks better than the previous one, IMO. The exact contents would need more brush up, though; e.g. the content of each jack could be shown in a debugfs node as well as the injection. Or the type and the mask-to-be-injected can be shown there, too.
OK, got it, will add more nodes for a jack, the nodes will bring more info of the jack to the userspace.
+static void _snd_jack_report(struct snd_jack *jack, int status, bool from_inject) +{
- struct snd_jack_kctl *jack_kctl;
- unsigned int mask_bits = 0;
+#ifdef CONFIG_SND_JACK_INPUT_DEV
- int i;
+#endif
- list_for_each_entry(jack_kctl, &jack->kctl_list, list) {
if (jack_kctl->sw_inject_enable == from_inject)snd_kctl_jack_report(jack->card, jack_kctl->kctl,status & jack_kctl->mask_bits);else if (jack_kctl->sw_inject_enable)mask_bits |= jack_kctl->mask_bits;- }
I'm wondering if it would be worth the code duplication to have the inject-variant of this code in a separate function. I find the above code to set up "mask_bits" a bit hard to read and this adds a layer of complexity to anyone just wanting to look at the regular jack report code path.
Yes, that's my impression, too. The logic is hard to follow.
I think it is really complicated, That is my design:
- If a jack_ctrl's sw_inject is enabled, the jack_report will only report status from injection (block hw events), if it is disabled, the jack_report will only report status from hw events (block injection). That is why I have to add a parameter from_inject
- A snd_jack could contain multi jack_ctrls, the snd_jack_report(status) is based on snd_jack instead of jack_ctrls, but sw_inject_enable is based on jack_ctrls instead of snd_jack. Suppose a snd_jack has 2 jack_ctrls A and B, A's sw_inject is enabled. Suppose Jack of A triggers a hw events and snd_jack_report() is called, the status should be blocked since A's sw_inject is enabled, also the input_dev's event of this jack_ctrl should be blocked too, I added mask_bits |= jack_kctl->mask_bits just for blocking the input-dev's report.
So far, I could not design a cleaner and simpler function to implement the idea above.
+static ssize_t sw_inject_enable_write(struct file *file,
const char __user *from, size_t count, loff_t *ppos)+{
- struct snd_jack_kctl *jack_kctl = file->private_data;
- char *buf;
- int ret, err;
- unsigned long enable;
- buf = kzalloc(count, GFP_KERNEL);
- if (!buf)
return -ENOMEM;- ret = simple_write_to_buffer(buf, count, ppos, from, count);
- err = kstrtoul(buf, 0, &enable);
- if (err) {
ret = err;goto exit;- }
- jack_kctl->sw_inject_enable = !!enable;
Here it's a bit annoying that after you disable sw_inject, the kcontrol values are not restored to reflrect actual hw state (until there are new jack events from hw). User-space cannot completely handle the save'n'restore as it cannot detect if real hw jack status changed during the sw-inject test. OTOH, this would require caching the most recent value and maybe not worth the effort.
Right, but I guess this can be ignored.
Or, as I mentioned in the above, we may expose the current value in each node instead, and writing a value to this node is treated as injection. Then the rest requirement is rather masking from the hardware update.
Also, I could add a hw_status_cache in the snd_jack_kctl{}, and use it to implement save-and-restore for the jack's state.
Thanks.
thanks,
Takashi