From d1e280334b7f0a1df441e08bd1f6a1bcc36b3bbb Mon Sep 17 00:00:00 2001 From: Michal Pecio Date: Mon, 18 May 2026 07:31:21 +0200 Subject: [PATCH] usb: core: Fix SuperSpeed root hub wMaxPacketSize There is no good reason to have wBytesPerInterval < wMaxPacketSize - either one is too low or the other too high, and we may want to warn about such descriptors. Start with cleaning up our own root hubs. USB 3.2 section 10.15.1 sets wMaxPacketSize and wBytesPerInterval of SuperSpeed hub status endpoints at 2 bytes, so reduce wMaxPacketSize from its former value of 4, which was derived from USB 2.0 spec and the kernel's USB_MAXCHILDREN limit. They don't apply because USB 3.2 10.15.2.1 specifies SuperSpeed hubs to have up to 15 ports. Suggested-by: Mathias Nyman Signed-off-by: Michal Pecio Link: https://patch.msgid.link/20260518073121.7bc1da0f.michal.pecio@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 89221f1ce769..b181b43a35dc 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -328,9 +328,7 @@ static const u8 ss_rh_config_descriptor[] = { USB_DT_ENDPOINT, /* __u8 ep_bDescriptorType; Endpoint */ 0x81, /* __u8 ep_bEndpointAddress; IN Endpoint 1 */ 0x03, /* __u8 ep_bmAttributes; Interrupt */ - /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8) - * see hub.c:hub_configure() for details. */ - (USB_MAXCHILDREN + 1 + 7) / 8, 0x00, + 0x02, 0x00, /* __le16 ep_wMaxPacketSize; 2 bytes per USB3 10.15.1 */ 0x0c, /* __u8 ep_bInterval; (256ms -- usb 2.0 spec) */ /* one SuperSpeed endpoint companion descriptor */