On Tue, Mar 15, 2016 at 8:59 PM, Stefan Roese sr@denx.de wrote:
Debugging has shown, that all USB hubs are being reset 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 Acked-by: Hans de Goede hdegoede@redhat.com Tested-by: Stephen Warren swarren@nvidia.com Cc: Marek Vasut marex@denx.de
Changes in v5: None Changes in v4:
- Minor rewording / fixes of the commit text
- Add Acked-by from Hans
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(-)
Tested-by: Bin Meng bmeng.cn@gmail.com