ALSA: usb-audio: scarlett2: Update initialisation sequence

The old initialisation code only works with Gen 2 devices. Replace it
with an initialisation sequence that works on both Gen 2 and Gen 3
devices.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/6e5c4fedb74b813872f6a4b7fba30b6c471fa63a.1624294591.git.g@b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c
index 6b77582..ed89e28 100644 (file)
--- a/sound/usb/mixer_scarlett_gen2.c
+++ b/sound/usb/mixer_scarlett_gen2.c
@@ -453,10 +453,12 @@ static int scarlett2_get_port_start_num(const struct scarlett2_ports *ports,
 #define SCARLETT2_USB_NOTIFY_MONITOR  0x00400000
 
 /* Commands for sending/receiving requests/responses */
+#define SCARLETT2_USB_CMD_INIT 0
 #define SCARLETT2_USB_CMD_REQ  2
 #define SCARLETT2_USB_CMD_RESP 3
 
-#define SCARLETT2_USB_INIT_SEQ  0x00000000
+#define SCARLETT2_USB_INIT_1    0x00000000
+#define SCARLETT2_USB_INIT_2    0x00000002
 #define SCARLETT2_USB_GET_METER 0x00001001
 #define SCARLETT2_USB_GET_MIX   0x00002001
 #define SCARLETT2_USB_SET_MIX   0x00002002
@@ -650,14 +652,19 @@ static int scarlett2_usb(
        if (err != resp_buf_size) {
                usb_audio_err(
                        mixer->chip,
-                       "Scarlett Gen 2 USB response result cmd %x was %d\n",
-                       cmd, err);
+                       "Scarlett Gen 2 USB response result cmd %x was %d "
+                       "expected %d\n",
+                       cmd, err, resp_buf_size);
                err = -EINVAL;
                goto unlock;
        }
 
+       /* cmd/seq/size should match except when initialising
+        * seq sent = 1, response = 0
+        */
        if (resp->cmd != req->cmd ||
-           resp->seq != req->seq ||
+           (resp->seq != req->seq &&
+               (le16_to_cpu(req->seq) != 1 || resp->seq != 0)) ||
            resp_size != le16_to_cpu(resp->size) ||
            resp->error ||
            resp->pad) {
@@ -675,7 +682,7 @@ static int scarlett2_usb(
                goto unlock;
        }
 
-       if (resp_size > 0)
+       if (resp_data && resp_size > 0)
                memcpy(resp_data, resp->data, resp_size);
 
 unlock:
@@ -1924,13 +1931,12 @@ static int scarlett2_find_fc_interface(struct usb_device *dev,
        return -EINVAL;
 }
 
-/* Initialise private data, sequence number, and get the USB data */
+/* Initialise private data */
 static int scarlett2_init_private(struct usb_mixer_interface *mixer,
                                  const struct scarlett2_device_info *info)
 {
        struct scarlett2_data *private =
                kzalloc(sizeof(struct scarlett2_data), GFP_KERNEL);
-       int err;
 
        if (!private)
                return -ENOMEM;
@@ -1948,12 +1954,35 @@ static int scarlett2_init_private(struct usb_mixer_interface *mixer,
        private->scarlett2_seq = 0;
        private->mixer = mixer;
 
-       err = scarlett2_find_fc_interface(mixer->chip->dev, private);
+       return scarlett2_find_fc_interface(mixer->chip->dev, private);
+}
+
+/* Cargo cult proprietary initialisation sequence */
+static int scarlett2_usb_init(struct usb_mixer_interface *mixer)
+{
+       struct usb_device *dev = mixer->chip->dev;
+       struct scarlett2_data *private = mixer->private_data;
+       u8 buf[24];
+       int err;
+
+       if (usb_pipe_type_check(dev, usb_sndctrlpipe(dev, 0)))
+               return -EINVAL;
+
+       /* step 0 */
+       err = scarlett2_usb_rx(dev, private->bInterfaceNumber,
+                              SCARLETT2_USB_CMD_INIT, buf, sizeof(buf));
        if (err < 0)
                return err;
 
-       /* Initialise the sequence number used for the proprietary commands */
-       return scarlett2_usb(mixer, SCARLETT2_USB_INIT_SEQ, NULL, 0, NULL, 0);
+       /* step 1 */
+       private->scarlett2_seq = 1;
+       err = scarlett2_usb(mixer, SCARLETT2_USB_INIT_1, NULL, 0, NULL, 0);
+       if (err < 0)
+               return err;
+
+       /* step 2 */
+       private->scarlett2_seq = 1;
+       return scarlett2_usb(mixer, SCARLETT2_USB_INIT_2, NULL, 0, NULL, 84);
 }
 
 /* Read configuration from the interface on start */
@@ -2128,11 +2157,16 @@ static int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer,
 {
        int err;
 
-       /* Initialise private data, sequence number, and get the USB data */
+       /* Initialise private data */
        err = scarlett2_init_private(mixer, info);
        if (err < 0)
                return err;
 
+       /* Send proprietary USB initialisation sequence */
+       err = scarlett2_usb_init(mixer);
+       if (err < 0)
+               return err;
+
        /* Read volume levels and controls from the interface */
        err = scarlett2_read_configs(mixer);
        if (err < 0)