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| H A D | minnowmax.h | 6e4d039aaaf87dcc83c743948c6bbcb49739e6a2 Wed Jul 19 13:50:09 UTC 2017 Bin Meng <bmeng.cn@gmail.com> x86: minnowmax: Add a environment variable for USB power-on delay
Occasionally it was observed that on Intel MinnowMax board, with a USB 2.0 device connected to the bottom port, when doing 'usb start' on the xHCI controller:
scanning bus 0 for devices... cannot reset port 3!?
But neither of the two USB ports is routed to xHCI root port 3. Adding some debug information shows that xHCI port 3 PORTSC register mysteriously reports both CCS = 1 and CSC = 1.
This is not seen every time. After increasing the timeout to wait for power to become stable, the issue is gone. So this indicates current default USB power-on delay (20ms) might be at a critical region where power is stable/unstable. U-Boot provides a mechanism to have a environment variable to override the default one. Add one for MinnowMax.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Stefan Roese <sr@denx.de> Tested-by: Stefan Roese <sr@denx.de>
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