usb: hub: Add quirk to decrease IN-ep poll interval for Microchip USB491x hub

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 <[e-mail]>
Reviewed-by: Alan Stern <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/core/hub.c

···
 #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
 
 /*
  * The SET_ADDRESS request timeout will be 500 ms when
···
 	if (id->driver_info & HUB_QUIRK_DISABLE_AUTOSUSPEND) {
 		hub->quirk_disable_autosuspend = 1;
 		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) {
···
       .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,