[PATCH 5.14 162/162] usb: gadget: f_uac2: Populate SS descriptors wBytesPerInterval

From: Greg Kroah-Hartman
Date: Mon Sep 27 2021 - 13:34:32 EST

From: Jack Pham <jackp@xxxxxxxxxxxxxx>

commit f0e8a206a2a53a919e1709c654cb65d519f7befb upstream.

For Isochronous endpoints, the SS companion descriptor's
wBytesPerInterval field is required to reserve bus time in order
to transmit the required payload during the service interval.
If left at 0, the UAC2 function is unable to transact data on its
playback or capture endpoints in SuperSpeed mode.

Since f_uac2 currently does not support any bursting this value can
be exactly equal to the calculated wMaxPacketSize.

Tested with Windows 10 as a host.

Fixes: f8cb3d556be3 ("usb: f_uac2: adds support for SS and SSP")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jack Pham <jackp@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210909174811.12534-3-jackp@xxxxxxxxxxxxxx
[jackp: Backport to 5.14 with minor conflict resolution]
Signed-off-by: Jack Pham <jackp@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/usb/gadget/function/f_uac2.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -951,6 +951,9 @@ afunc_bind(struct usb_configuration *cfg
agdev->out_ep_maxpsize = max_t(u16, agdev->out_ep_maxpsize,

+ ss_epin_desc_comp.wBytesPerInterval = ss_epin_desc.wMaxPacketSize;
+ ss_epout_desc_comp.wBytesPerInterval = ss_epout_desc.wMaxPacketSize;
hs_epout_desc.bEndpointAddress = fs_epout_desc.bEndpointAddress;
hs_epin_fback_desc.bEndpointAddress = fs_epin_fback_desc.bEndpointAddress;
hs_epin_desc.bEndpointAddress = fs_epin_desc.bEndpointAddress;