From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Thu, 10 Mar 2016 17:07:14 -0700 Subject: [U-Boot] [PATCH 5/6] usb: Don't reset the USB hub a 2nd time In-Reply-To: <1457625012-1268-6-git-send-email-sr@denx.de> References: <1457625012-1268-1-git-send-email-sr@denx.de> <1457625012-1268-6-git-send-email-sr@denx.de> Message-ID: <56E20C32.7070507@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 For the other patches I agree with Hans' comments.