I'm design a usb device, the max current is 500mA, normal is 300mA. Now I face a proble : my device can work on pc and many notebook, but on some notebook it does't work.
What's special on notebook's USB port ? I see the configration of notebook that the port is 500mA.
The 500 mA is shared between the devices. Does the notebook have any internal devices that are USB? Do you report a 500 mA device in your descriptor? Try to report 100 mA to verify this is the problem
no other device. The notebook which I tried is IBM's. It has a DVD which is plug-in device, but it's not a USB device. I tried the 100mA , my usb device doesn't work. But it can work on the hub which connect to this notebook USB port.
I think my device pass enumeration on both the notebook, external hub and other PCs ,because it's been seen the current of the device is 500mA,which is the device configed.