[PATCH AUTOSEL 6.1 06/27] usb: hub: Add quirk to decrease IN-ep poll interval for Microchip USB491x hub

Sasha Levin
2024-01-28T16:14:37Z

From: Hardik Gajjar <hgajjar@de.adit-jv.com>

[ Upstream commit 855d75cf8311fee156fabb5639bb53757ca83dd4 ]

There is a potential delay in notifying Linux USB drivers of downstream
USB bus activity when connecting a high-speed or superSpeed device via the
Microchip USB491x hub. This delay is due to the fixed bInterval value of
12 in the silicon of the Microchip USB491x hub.

Microchip requested to ignore the device descriptor and decrease that
value to 9 as it was too late to modify that in silicon.

This patch speeds up the USB enummeration process that helps to pass
Apple Carplay certifications and improve the User experience when utilizing
the USB device via Microchip Multihost USB491x Hub.

A new hub quirk HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL speeds up
the notification process for Microchip USB491x hub by limiting
the maximum bInterval value to 9.

Signed-off-by: Hardik Gajjar <hgajjar@de.adit-jv.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20231205181829.127353-2-hgajjar@de.adit-jv.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/core/hub.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 9163fd5af046..4f181110d00d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -47,12 +47,18 @@
#define USB_VENDOR_TEXAS_INSTRUMENTS 0x0451
#define USB_PRODUCT_TUSB8041_USB3 0x8140
#define USB_PRODUCT_TUSB8041_USB2 0x8142
+#define USB_VENDOR_MICROCHIP 0x0424
+#define USB_PRODUCT_USB4913 0x4913
+#define USB_PRODUCT_USB4914 0x4914
+#define USB_PRODUCT_USB4915 0x4915
#define HUB_QUIRK_CHECK_PORT_AUTOSUSPEND BIT(0)
#define HUB_QUIRK_DISABLE_AUTOSUSPEND BIT(1)
+#define HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL BIT(2)

#define USB_TP_TRANSMISSION_DELAY 40 /* ns */
#define USB_TP_TRANSMISSION_DELAY_MAX 65535 /* ns */
#define USB_PING_RESPONSE_TIME 400 /* ns */
+#define USB_REDUCE_FRAME_INTR_BINTERVAL 9

/* Protect struct usb_device->state and ->children members
* Note: Both are also protected by ->dev.sem, except that ->state can
@@ -1904,6 +1910,14 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
usb_autopm_get_interface_no_resume(intf);
}

+ if ((id->driver_info & HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL) &&
+ desc->endpoint[0].desc.bInterval > USB_REDUCE_FRAME_INTR_BINTERVAL) {
+ desc->endpoint[0].desc.bInterval =
+ USB_REDUCE_FRAME_INTR_BINTERVAL;
+ /* Tell the HCD about the interrupt ep's new bInterval */
+ usb_set_interface(hdev, 0, 0);
+ }
+
if (hub_configure(hub, &desc->endpoint[0].desc) >= 0) {
onboard_hub_create_pdevs(hdev, &hub->onboard_hub_devs);

@@ -5885,6 +5899,21 @@ static const struct usb_device_id hub_id_table[] = {
.idVendor = USB_VENDOR_TEXAS_INSTRUMENTS,
.idProduct = USB_PRODUCT_TUSB8041_USB3,
.driver_info = HUB_QUIRK_DISABLE_AUTOSUSPEND},
+ { .match_flags = USB_DEVICE_ID_MATCH_VENDOR
+ | USB_DEVICE_ID_MATCH_PRODUCT,
+ .idVendor = USB_VENDOR_MICROCHIP,
+ .idProduct = USB_PRODUCT_USB4913,
+ .driver_info = HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL},
+ { .match_flags = USB_DEVICE_ID_MATCH_VENDOR
+ | USB_DEVICE_ID_MATCH_PRODUCT,
+ .idVendor = USB_VENDOR_MICROCHIP,
+ .idProduct = USB_PRODUCT_USB4914,
+ .driver_info = HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL},
+ { .match_flags = USB_DEVICE_ID_MATCH_VENDOR
+ | USB_DEVICE_ID_MATCH_PRODUCT,
+ .idVendor = USB_VENDOR_MICROCHIP,
+ .idProduct = USB_PRODUCT_USB4915,
+ .driver_info = HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL},
{ .match_flags = USB_DEVICE_ID_MATCH_DEV_CLASS,
.bDeviceClass = USB_CLASS_HUB},
{ .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS,
--
2.43.0