On 10.03.2016 20:13, Hans de Goede wrote:
Hi,
On 10-03-16 16:50, Stefan Roese wrote:
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 if CONFIG_USB_FAST_SCAN
is defined. Resulting in faster USB scan time. Here the current
number:
Without this patch:
=> time usb start
starting USB...
USB0: USB EHCI 1.00
scanning bus 0 for devices... 9 USB Device(s) found
time: 6.319 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: 3.777 seconds
So ~2.5 seconds of USB scanning time reduction.
Again, this 2nd reset is only removed if CONFIG_USB_FAST_SCAN is
defined. Once more tests are done on multiple other platforms we
can decide to remove this 2nd reset completely.
I see no reason to make the removal conditional, I believe that
this is some relic workaround for likely long fixed bugs and
we should just remove it completely (for v2016.07).
Thanks. I'll make this change unconditional in the next patch version
as well.
Thanks,
Stefan
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
