On Thu, 01 Jun 2006 02:18:20 -0700 David Liontooth <[EMAIL PROTECTED]> wrote:
> Starting with 2.6.16, some USB devices fail unnecessarily on unpowered > hubs. Alan Stern explains, > > "The idea is that the kernel now keeps track of USB power budgets. When a > bus-powered device requires more current than its upstream hub is capable > of providing, the kernel will not configure it. > > Computers' USB ports are capable of providing a full 500 mA, so devices > plugged directly into the computer will work okay. However unpowered hubs > can provide only 100 mA to each port. Some devices require (or claim they > require) more current than that. As a result, they don't get configured > when plugged into an unpowered hub." > > http://www.mail-archive.com/linux-usb-devel@lists.sourceforge.net/msg43480.html > > This is generating a lot of grief and appears to be unnecessarily > strict. Common USB sticks with a MaxPower value just above 100mA, for > instance, typically work fine on unpowered hubs supplying 100mA. > > Is a more user-friendly solution possible? Could the shortfall > information be passed to udev, which would allow rules to be written per > device? > (added linux-usb cc) Yes, it sounds like we're being non-real-worldly here. This change apparently broke things. Did it actually fix anything as well? ------------------------------------------------------- All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
