Messages in this thread | | | Date | Thu, 19 Apr 2018 12:19:15 +0200 | From | Takashi Iwai <> | Subject | Re: [alsa-devel] [PATCH 4/4] ALSA: usb: add UAC3 BADD profiles support |
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On Sat, 14 Apr 2018 00:24:26 +0200, Ruslan Bilovol wrote: > > +static void build_feature_ctl_badd(struct usb_mixer_interface *mixer, > + unsigned int ctl_mask, int control, int unitid, > + const struct usbmix_name_map *badd_map) > +{ .... > + kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval); > + > + if (!kctl) { > + usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
No need for error message after malloc failure. The kernel is already chatty about it.
> +static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer, > + int ctrlif) > +{ > + struct usb_device *dev = mixer->chip->dev; > + struct usb_interface_assoc_descriptor *assoc; > + int badd_profile = mixer->chip->badd_profile; > + const struct usbmix_ctl_map *map; > + int p_chmask = 0, c_chmask = 0, st_chmask = 0; > + int i; > + > + assoc = usb_ifnum_to_if(dev, ctrlif)->intf_assoc; > + > + /* Detect BADD capture/playback channels from AS EP descriptors */ > + for (i = 0; i < assoc->bInterfaceCount; i++) { > + int intf = assoc->bFirstInterface + i; > + > + if (intf != ctrlif) {
In this case, it's better to skip like
if (intf == ctrlif) continue;
so that we can save an indentation for the whole long block.
> + switch (badd_profile) { > + default: > + return -EINVAL; > + case UAC3_FUNCTION_SUBCLASS_GENERIC_IO: > + /* > + * BAIF, BAOF or combination of both > + * IN: Mono or Stereo cfg, Mono alt possible > + * OUT: Mono or Stereo cfg, Mono alt possible > + */ > + /* c_chmask := DYNAMIC */ > + /* p_chmask := DYNAMIC */ > + if (!c_chmask && !p_chmask) { > + usb_audio_err(mixer->chip, > + "BADD GENERIC_IO profile: no channels?\n"); > + return -EINVAL; > + } > + break;
Maybe we can simplify the whole switch/case with a table lookup. For example,
for (f = uac3_func_tables; f->name; f++) { if (badd_profile == f->subclass) break; } if (!f->name) return -EINVAL; if (!uac3_func_has_valid_channels(mixer, f, c_chmask, p_chmask)) return -EINVAL; st_chmask = f->st_chmask;
and in uac3_func_has_valid_channels(),
static bool uac3_func_has_valid_channels() { if ((f->c_chmask < 0 && !c_chmask) || (f->c_chmask >= 0 && f->c_chmask != c_chmask)) { usb_audio_warn(mixer->chip, "BAAD %s c_chmask mismatch", f->name); return false; } if ((f->p_chmask < 0 && !p_chmask) || (f->p_chmask >= 0 && f->p_chmask != p_chmask)) { usb_audio_warn(mixer->chip, "BAAD %s p_chmask mismatch", f->name); return false; } return true; }
thanks,
Takashi
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