From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Date: Sat, 2 Apr 2016 23:21:10 +0200 Subject: [U-Boot] [PATCH v5 4/4] usb: Change power-on / scanning timeout handling In-Reply-To: <56FEF496.5010305@denx.de> References: <1458046755-15934-1-git-send-email-sr@denx.de> <1458046755-15934-5-git-send-email-sr@denx.de> <56FEF496.5010305@denx.de> Message-ID: <570037C6.1040405@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi, On 04/02/2016 12:22 AM, Marek Vasut wrote: > On 03/15/2016 01:59 PM, Stefan Roese wrote: >> This patch changes the USB port scanning procedure and timeout >> handling in the following ways: >> >> a) >> The power-on delay in usb_hub_power_on() is now reduced to a value of >> max(100ms, "hub->desc.bPwrOn2PwrGood * 2"). The code does not wait >> using mdelay, instead usb_hub_power_on() will wait before querying >> the device in the scanning loop later. The total timeout for this >> hub, which is 1 second + "hub->desc.bPwrOn2PwrGood * 2" is calculated >> and will be used in the following per-port scanning loop as the timeout >> to detect active USB devices on this hub. >> >> b) >> Don't delay the minimum delay (for power to stabilize) in >> usb_hub_power_on(). Instead skip querying these devices in the scannig >> loop until the delay time is reached. >> >> c) >> The ports are now scanned in a quasi parallel way. The current code did >> wait for each (unconnected) port to reach its timeout and only then >> continue with the next port. This patch now changes this to scan all >> ports of all USB hubs quasi simultaneously. For this, all ports are added >> to a scanning list. This list is scanned until all ports are ready >> by either a) reaching the connection timeout (calculated earlier), or >> by b) detecting a USB device. This results in a faster USB scan time as >> the recursive scanning of USB hubs connected to the hub that's currently >> being scanned will start earlier. >> >> One small functional change to the original code is, that ports with >> overcurrent detection will now get rescanned multiple times >> (PORT_OVERCURRENT_MAX_SCAN_COUNT). >> >> Without this patch: >> starting USB... >> USB0: USB EHCI 1.00 >> scanning bus 0 for devices... 9 USB Device(s) found >> >> time: 20.163 seconds >> >> With this patch: >> starting USB... >> USB0: USB EHCI 1.00 >> scanning bus 0 for devices... 9 USB Device(s) found >> >> time: 1.822 seconds >> >> So ~18.3 seconds of USB scanning time reduction. >> >> Signed-off-by: Stefan Roese >> Acked-by: Hans de Goede >> Tested-by: Stephen Warren > > This breaks DWC2 on SoCkit, I can no longer detect any USB device. > USB works without this patch though. Ideas? Have you tried simply adding a large sleep before the initial uart, or doing an "usb reset" after the initial scan ? The biggest change here is the change in timing ... Also try defining debug printf in usb_hub.c and see what output you get ? Regards, Hans