On 03/10/2016 08:50 AM, 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.
This patch, after modifying the patch to unconditionally remove the code
rather than only conditionally,
Tested-by: Stephen Warren <swar...@nvidia.com>
For the other patches I agree with Hans' comments.
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