[PATCH 2/2] ALSA: usb-audio: Generic application of implicit fb to Roland/BOSS devices

[Takashi Iwai <tiwai@suse.de>]

Through the examinations and experiments with lots of Roland and BOSS
USB-audio devices, we found out that the recently introduced
full-duplex operations with the implicit feedback mode work fine for
quite a few devices, while the others need only the capture-side quirk
to enforce the full-duplex mode.  The recent commit d86f43b17ed4
("ALSA: usb-audio: Add support for many Roland devices' implicit
feedback quirks") tried to add such quirk entries manually in the
lists, but this turned out to be too many and error-prone, hence it
was reverted again.

This patch is another attempt to cover those missing Roland/BOSS
devices but in a more generic way.  It matches the devices with the
vendor ID 0x0582, and checks whether they are with both ASYNC sync
types or ASYNC is only for capture device.  In the former case, it's
the device with the implicit feedback mode, and applies accordingly.
In both cases, the capture stream requires always the full-duplex
mode, and we apply the known capture quirk for that, too.

Basically the already existing BOSS device quirk entries become
redundant after this generic matching, so those are removed.  Although
the capture_implicit_fb_quirks[] table became empty and superfluous, I
keep it for now, so that people can put a special device easily at any
time later again.

Link: https://lore.kernel.org/r/CAOsVg8rA61B=005_VyUwpw3piVwA7Bo5fs1GYEB054efyzGjLw@mail.gmail.com
Link: https://lore.kernel.org/r/20210414083255.9527-1-tiwai@suse.de
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=212519
Tested-by: Lucas Endres <jaffa225man@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/implicit.c | 92 +++++++++++++++++++++++++++++---------------
 1 file changed, 62 insertions(+), 30 deletions(-)

diff --git a/sound/usb/implicit.c b/sound/usb/implicit.c
index 94acfaa7f2ef..590a0dbba7a2 100644
--- a/sound/usb/implicit.c
+++ b/sound/usb/implicit.c
@@ -79,15 +79,6 @@ static const struct snd_usb_implicit_fb_match playback_implicit_fb_quirks[] = {
 
 /* Implicit feedback quirk table for capture: only FIXED type */
 static const struct snd_usb_implicit_fb_match capture_implicit_fb_quirks[] = {
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x0130, 0x0d, 0x01), /* BOSS BR-80 */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x0171, 0x0d, 0x01), /* BOSS RC-505 */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x0185, 0x0d, 0x01), /* BOSS GP-10 */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x0189, 0x0d, 0x01), /* BOSS GT-100v2 */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x01d6, 0x0d, 0x01), /* BOSS GT-1 */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x01d8, 0x0d, 0x01), /* BOSS Katana */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x01e5, 0x0d, 0x01), /* BOSS GT-001 */
-	IMPLICIT_FB_BOTH_DEV(0x0582, 0x0203, 0x0d, 0x01), /* BOSS AD-10 */
-
 	{} /* terminator */
 };
 
@@ -145,30 +136,70 @@ static int add_generic_uac2_implicit_fb(struct snd_usb_audio *chip,
 				       ifnum, alts);
 }
 
-/* Like the function above, but specific to Roland with vendor class and hack */
+static bool roland_sanity_check_iface(struct usb_host_interface *alts)
+{
+	if (alts->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
+	    (alts->desc.bInterfaceSubClass != 2 &&
+	     alts->desc.bInterfaceProtocol != 2) ||
+	    alts->desc.bNumEndpoints < 1)
+		return false;
+	return true;
+}
+
+/* Like the UAC2 case above, but specific to Roland with vendor class and hack */
 static int add_roland_implicit_fb(struct snd_usb_audio *chip,
 				  struct audioformat *fmt,
-				  unsigned int ifnum,
-				  unsigned int altsetting)
+				  struct usb_host_interface *alts)
 {
-	struct usb_host_interface *alts;
 	struct usb_endpoint_descriptor *epd;
 
-	alts = snd_usb_get_host_interface(chip, ifnum, altsetting);
-	if (!alts)
+	if (!roland_sanity_check_iface(alts))
 		return 0;
-	if (alts->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
-	    (alts->desc.bInterfaceSubClass != 2 &&
-	     alts->desc.bInterfaceProtocol != 2) ||
-	    alts->desc.bNumEndpoints < 1)
+	/* only when both streams are with ASYNC type */
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_out(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+
+	/* check capture EP */
+	alts = snd_usb_get_host_interface(chip,
+					  alts->desc.bInterfaceNumber + 1,
+					  alts->desc.bAlternateSetting);
+	if (!alts || !roland_sanity_check_iface(alts))
 		return 0;
 	epd = get_endpoint(alts, 0);
 	if (!usb_endpoint_is_isoc_in(epd) ||
-	    (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
-					USB_ENDPOINT_USAGE_IMPLICIT_FB)
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
 		return 0;
+	chip->playback_first = 1;
 	return add_implicit_fb_sync_ep(chip, fmt, epd->bEndpointAddress, 0,
-				       ifnum, alts);
+				       alts->desc.bInterfaceNumber, alts);
+}
+
+/* capture quirk for Roland device; always full-duplex */
+static int add_roland_capture_quirk(struct snd_usb_audio *chip,
+				    struct audioformat *fmt,
+				    struct usb_host_interface *alts)
+{
+	struct usb_endpoint_descriptor *epd;
+
+	if (!roland_sanity_check_iface(alts))
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_in(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+
+	alts = snd_usb_get_host_interface(chip,
+					  alts->desc.bInterfaceNumber - 1,
+					  alts->desc.bAlternateSetting);
+	if (!alts || !roland_sanity_check_iface(alts))
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_out(epd))
+		return 0;
+	return add_implicit_fb_sync_ep(chip, fmt, epd->bEndpointAddress, 0,
+				       alts->desc.bInterfaceNumber, alts);
 }
 
 /* Playback and capture EPs on Pioneer devices share the same iface/altset
@@ -306,14 +337,8 @@ static int audioformat_implicit_fb_quirk(struct snd_usb_audio *chip,
 	}
 
 	/* Roland/BOSS implicit feedback with vendor spec class */
-	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
-	    alts->desc.bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
-	    alts->desc.bInterfaceProtocol == 2 &&
-	    alts->desc.bNumEndpoints == 1 &&
-	    USB_ID_VENDOR(chip->usb_id) == 0x0582 /* Roland */) {
-		if (add_roland_implicit_fb(chip, fmt,
-					   alts->desc.bInterfaceNumber + 1,
-					   alts->desc.bAlternateSetting))
+	if (USB_ID_VENDOR(chip->usb_id) == 0x0582) {
+		if (add_roland_implicit_fb(chip, fmt, alts) > 0)
 			return 1;
 	}
 
@@ -345,6 +370,13 @@ static int audioformat_capture_quirk(struct snd_usb_audio *chip,
 	if (p && (p->type == IMPLICIT_FB_FIXED || p->type == IMPLICIT_FB_BOTH))
 		return add_implicit_fb_sync_ep(chip, fmt, p->ep_num, 0,
 					       p->iface, NULL);
+
+	/* Roland/BOSS need full-duplex streams */
+	if (USB_ID_VENDOR(chip->usb_id) == 0x0582) {
+		if (add_roland_capture_quirk(chip, fmt, alts) > 0)
+			return 1;
+	}
+
 	if (is_pioneer_implicit_fb(chip, alts))
 		return 1; /* skip the quirk, also don't handle generic sync EP */
 	return 0;
-- 
2.26.2