On Thu, Nov 30, 2023 at 09:48:55AM +0100, Hardik Gajjar wrote: > 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@xxxxxxxxxxxxxx> > --- > changes since version 1: > - Move implementation from config.c and quirk.c to hub.c as this is hub > specific changes. > - Improve commit message. > - Link to v1 - https://lore.kernel.org/all/20231123081948.58776-1-hgajjar@xxxxxxxxxxxxxx/ > --- > drivers/usb/core/hub.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index b4584a0cd484..3d26d942fcae 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 0x01 > #define HUB_QUIRK_DISABLE_AUTOSUSPEND 0x02 > +#define HUB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL 0x08 Why not use 0x04, the next available bit? > > #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 > @@ -1927,6 +1933,12 @@ 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; As I mentioned in an earlier email, you need to do: /* Tell the HCD about the interrupt ep's new bInterval */ usb_set_interface(hdev, 0, 0); here. Everything else looks okay (and much better than before). Alan Stern > + } > + > if (hub_configure(hub, &desc->endpoint[0].desc) >= 0) { > onboard_hub_create_pdevs(hdev, &hub->onboard_hub_devs); > > @@ -5918,6 +5930,21 @@ 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, > -- > 2.17.1 >
