So far bInterval for HS and SS was fixed at 4, disallowing faster
samplerates. The patch determines the largest bInterval (4 to 1) for
which the required bandwidth of the max samplerate fits the max allowed
packet size. If the required bandwidth exceeds max bandwidth for
single-packet mode (ep->mc=1), bInterval is left at 1.
The FS mode is left at fixed bInterval=1.
Signed-off-by: Pavel Hofman <pavel.hofman@xxxxxxxxxxx>
---
drivers/usb/gadget/function/f_uac2.c | 90 +++++++++++++++++-----------
1 file changed, 55 insertions(+), 35 deletions(-)
diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 984f757de5a4..e72f6f42e1b7 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -333,7 +333,7 @@ static struct usb_endpoint_descriptor fs_epout_desc = {
.bEndpointAddress = USB_DIR_OUT,
/* .bmAttributes = DYNAMIC */
/* .wMaxPacketSize = DYNAMIC */
- .bInterval = 1,
+ /* .bInterval = DYNAMIC */
};
static struct usb_endpoint_descriptor hs_epout_desc = {
@@ -342,7 +342,7 @@ static struct usb_endpoint_descriptor hs_epout_desc = {
/* .bmAttributes = DYNAMIC */
/* .wMaxPacketSize = DYNAMIC */
- .bInterval = 4,
+ /* .bInterval = DYNAMIC */
};
static struct usb_endpoint_descriptor ss_epout_desc = {
@@ -352,7 +352,7 @@ static struct usb_endpoint_descriptor ss_epout_desc = {
.bEndpointAddress = USB_DIR_OUT,
/* .bmAttributes = DYNAMIC */
/* .wMaxPacketSize = DYNAMIC */
- .bInterval = 4,
+ /* .bInterval = DYNAMIC */
};
static struct usb_ss_ep_comp_descriptor ss_epout_desc_comp = {
@@ -467,7 +467,7 @@ static struct usb_endpoint_descriptor fs_epin_desc = {
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
/* .wMaxPacketSize = DYNAMIC */
- .bInterval = 1,
+ /* .bInterval = DYNAMIC */
};
static struct usb_endpoint_descriptor hs_epin_desc = {
@@ -476,7 +476,7 @@ static struct usb_endpoint_descriptor hs_epin_desc = {
.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
/* .wMaxPacketSize = DYNAMIC */
- .bInterval = 4,
+ /* .bInterval = DYNAMIC */
};
static struct usb_endpoint_descriptor ss_epin_desc = {
@@ -486,7 +486,7 @@ static struct usb_endpoint_descriptor ss_epin_desc = {
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ASYNC,
/* .wMaxPacketSize = DYNAMIC */
- .bInterval = 4,
+ /* .bInterval = DYNAMIC */
};
static struct usb_ss_ep_comp_descriptor ss_epin_desc_comp = {
@@ -659,29 +659,11 @@ static int get_max_srate(const int *srates)
return max_srate;
}
-static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
- struct usb_endpoint_descriptor *ep_desc,
- enum usb_device_speed speed, bool is_playback)
+static int get_max_bw_for_binterval(const struct f_uac2_opts *uac2_opts,
+ u8 binterval, unsigned int factor, bool is_playback)
{
int chmask, srate, ssize;
- u16 max_size_bw, max_size_ep;
- unsigned int factor;
-
- switch (speed) {
- case USB_SPEED_FULL:
- max_size_ep = 1023;
- factor = 1000;
- break;
-
- case USB_SPEED_HIGH:
- case USB_SPEED_SUPER:
- max_size_ep = 1024;
- factor = 8000;
- break;
-
- default:
- return -EINVAL;
- }
+ u16 max_size_bw;
if (is_playback) {
chmask = uac2_opts->p_chmask;
@@ -699,14 +681,52 @@ static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
srate = srate * (1000 + uac2_opts->fb_max) / 1000;
// updated srate is always bigger, therefore DIV_ROUND_UP always yields +1
max_size_bw = num_channels(chmask) * ssize *
- (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))));
+ (DIV_ROUND_UP(srate, factor / (1 << (binterval - 1))));
} else {
// adding 1 frame provision for Win10
max_size_bw = num_channels(chmask) * ssize *
- (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))) + 1);
+ (DIV_ROUND_UP(srate, factor / (1 << (binterval - 1))) + 1);
}
+ return max_size_bw;
+}
+
+static int set_ep_max_packet_size_bint(const struct f_uac2_opts *uac2_opts,
+ struct usb_endpoint_descriptor *ep_desc,
+ enum usb_device_speed speed, bool is_playback)
+{
+ u16 max_size_bw, max_size_ep;
+ u8 binterval;
+
+ switch (speed) {
+ case USB_SPEED_FULL:
+ max_size_ep = 1023;
+ // fixed
+ binterval = 1;
+ max_size_bw = get_max_bw_for_binterval(uac2_opts, binterval, 1000,
+ is_playback);
+ break;
+
+ case USB_SPEED_HIGH:
+ case USB_SPEED_SUPER:
+ max_size_ep = 1024;
+ // checking bInterval from 4 (= 1ms) to 1 if the required bandwidth fits
+ for (binterval = 4; binterval > 0; --binterval) {
+ max_size_bw = get_max_bw_for_binterval(uac2_opts, binterval, 8000,
+ is_playback);
+ if (max_size_bw <= max_size_ep) {
+ // found largest bInterval/max_size_bw fitting max_size_ep
+ break;
+ }
+ }
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw,
max_size_ep));
+ ep_desc->bInterval = binterval;
return 0;
}
@@ -1119,42 +1139,42 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
}
/* Calculate wMaxPacketSize according to audio bandwidth */
- ret = set_ep_max_packet_size(uac2_opts, &fs_epin_desc, USB_SPEED_FULL,
+ ret = set_ep_max_packet_size_bint(uac2_opts, &fs_epin_desc, USB_SPEED_FULL,
true);
if (ret < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
return ret;
}
- ret = set_ep_max_packet_size(uac2_opts, &fs_epout_desc, USB_SPEED_FULL,
+ ret = set_ep_max_packet_size_bint(uac2_opts, &fs_epout_desc, USB_SPEED_FULL,
false);
if (ret < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
return ret;
}
- ret = set_ep_max_packet_size(uac2_opts, &hs_epin_desc, USB_SPEED_HIGH,
+ ret = set_ep_max_packet_size_bint(uac2_opts, &hs_epin_desc, USB_SPEED_HIGH,
true);
if (ret < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
return ret;
}
- ret = set_ep_max_packet_size(uac2_opts, &hs_epout_desc, USB_SPEED_HIGH,
+ ret = set_ep_max_packet_size_bint(uac2_opts, &hs_epout_desc, USB_SPEED_HIGH,
false);
if (ret < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
return ret;
}
- ret = set_ep_max_packet_size(uac2_opts, &ss_epin_desc, USB_SPEED_SUPER,
+ ret = set_ep_max_packet_size_bint(uac2_opts, &ss_epin_desc, USB_SPEED_SUPER,
true);
if (ret < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
return ret;
}
- ret = set_ep_max_packet_size(uac2_opts, &ss_epout_desc, USB_SPEED_SUPER,
+ ret = set_ep_max_packet_size_bint(uac2_opts, &ss_epout_desc, USB_SPEED_SUPER,
false);
if (ret < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
--
2.25.1
