Re: [alsa-devel] [PATCH v2 3/3] ALSA: hda: add support for Huawei WMI MicMute LED

On Fri, 02 Nov 2018 19:12:44 +0100, Andy Shevchenko wrote:

...

•   if (action == HDA_FIXUP_ACT_PROBE) {
  

•           if (!huawei_wmi_micmute_led_set_func)
  

•                   huawei_wmi_micmute_led_set_func = symbol_request(huawei_wmi_micmute_led_set);
  

•           if (!huawei_wmi_micmute_led_set_func) {
  

•                   codec_warn(codec, "Failed to find huawei_wmi symbol huawei_wmi_micmute_led_set\n");
  

•                   return;
  

•           }
  

•           removefunc = (huawei_wmi_micmute_led_set_func(false) < 0)
  

•                   || (snd_hda_gen_add_micmute_led(codec, update_huawei_wmi_micmute_led) < 0);
  

•   }
  

•   if (huawei_wmi_micmute_led_set_func && (action == HDA_FIXUP_ACT_FREE || removefunc)) {
  

•           symbol_put(huawei_wmi_micmute_led_set);
  

•           huawei_wmi_micmute_led_set_func = NULL;
  

•   }
  

+}

Takashi, is it a way how the rest sound drivers are written? B/c this symbol_request(s) look to me a bit ugly.

It's a workaround for not having a hard dependency. The HD-audio codec driver is generic, and we don't want to load the multiple WMI drivers always for using a Realtek codec.

Ugly, yes, but simple enough.

thanks,

Takashi