Debugging has shown, that all USB hubs are being resetted twice while USB scanning. This introduces additional delays and makes USB scanning even more slow. Testing has shown that this 2nd USB hub reset doesn't seem to be necessary.
This patch now removes this 2nd USB hub reset. Resulting in faster USB scan time. Here the current numbers:
Without this patch: => time usb start starting USB... USB0: USB EHCI 1.00 scanning bus 0 for devices... 9 USB Device(s) found
time: 24.003 seconds
With this patch: => time usb start starting USB... USB0: USB EHCI 1.00 scanning bus 0 for devices... 9 USB Device(s) found
time: 20.392 seconds
So ~3.6 seconds of USB scanning time reduction.
Signed-off-by: Stefan Roese sr@denx.de Cc: Simon Glass sjg@chromium.org Cc: Hans de Goede hdegoede@redhat.com Tested-by: Stephen Warren swarren@nvidia.com Cc: Marek Vasut marex@denx.de
---
Changes in v3: None Changes in v2: - Make this change unconditional - Add Tested-by from Stephen
common/usb.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-)
diff --git a/common/usb.c b/common/usb.c index c7b8b0e..45a5a0f 100644 --- a/common/usb.c +++ b/common/usb.c @@ -919,19 +919,8 @@ __weak int usb_alloc_device(struct usb_device *udev)
static int usb_hub_port_reset(struct usb_device *dev, struct usb_device *hub) { - if (hub) { - unsigned short portstatus; - int err; - - /* reset the port for the second time */ - err = legacy_hub_port_reset(hub, dev->portnr - 1, &portstatus); - if (err < 0) { - printf("\n Couldn't reset port %i\n", dev->portnr); - return err; - } - } else { + if (!hub) usb_reset_root_port(dev); - }
return 0; }