[PATCH 4/4] usb: gadget: dummy_hcd: set no_sg_constraint on the host controller

[Igor Skalkin]

dummy_hcd copies data in software and has no hardware DMA alignment
requirement.  Set no_sg_constraint = 1 so the USB core does not reject
SG URBs whose non-final segments are not a multiple of the endpoint
maxpacket size.

For SuperSpeed bulk endpoints maxpacket is 1024 bytes; usbtest generates
SG lists with varying segment sizes (e.g. 512 bytes) that are valid
transfers but not maxpacket-aligned, causing usb_submit_urb to return
-EINVAL before the URB reaches the host controller.

Assisted-by: OpenCode:claude-sonnet-5
Signed-off-by: Igor Skalkin <igor.skalkin@xxxxxxxxxxxxxxxx>
---
 drivers/usb/gadget/udc/dummy_hcd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index 7597c9e9fa66..2cfb1d035b34 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -2550,6 +2550,7 @@ static int dummy_setup(struct usb_hcd *hcd)
 
 	dum = *((void **)dev_get_platdata(hcd->self.controller));
 	hcd->self.sg_tablesize = ~0;
+	hcd->self.no_sg_constraint = 1;
 	if (usb_hcd_is_primary_hcd(hcd)) {
 		dum->hs_hcd = hcd_to_dummy_hcd(hcd);
 		dum->hs_hcd->dum = dum;
-- 
2.49.0