On 12/10/2011 05:29 PM, Remy Bohmer wrote:
Hi,
2011/12/5 Vincent Palatin vpalatin@chromium.org:
According to EHCI specification v1.0, the controller should stabilize the power on a port at most 20 ms after the port power bit transition. So, we put this setting in the virtual descriptor corresponding field, (bPwrOn2PwrGood = 10 => 10 x 2ms = 20ms), this saves about 500ms at each controller initialization/enumeration.
Signed-off-by: Vincent Palatin vpalatin@chromium.org
drivers/usb/host/ehci-hcd.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
Applied to u-boot-usb.
I just realized that this patch breaks "usb start" on my mx53loco board:
MX53LOCO U-Boot > usb start (Re)start USB... USB: Register 10011 NbrPorts 1 USB EHCI 1.00 scanning bus for devices... 1 USB Device(s) found scanning bus for storage devices... 0 Storage Device(s) found scanning bus for ethernet devices... 0 Ethernet Device(s) found
MX53LOCO U-Boot > usb start (Re)start USB... USB: Register 10011 NbrPorts 1 USB EHCI 1.00 scanning bus for devices... 2 USB Device(s) found scanning bus for storage devices... 0 Storage Device(s) found scanning bus for ethernet devices... 1 Ethernet Device(s) found
The device is not found at the first attempt. Obviously, a value of 10 for bPwrOn2PwrGood seems too short but 20 works fine. Would that be a resonable compromise? If yes, I could send a patch.
Wolfgang.
Wolfgang.