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Re: Crash in usb_keyboard

From: Pavel Roskin
Subject: Re: Crash in usb_keyboard
Date: Sun, 03 May 2009 00:25:31 -0400

On Sat, 2009-05-02 at 13:39 +0200, Robert Millan wrote:
> On Mon, Apr 27, 2009 at 11:55:10PM -0400, Pavel Roskin wrote:
> > Hello!
> > 
> > Running "terminal_input.usb_keyboard" crashed GRUB (or qemu it's running
> > in).  It turns out we never check if usbdev in term/usb_keyboard.c is
> > not NULL.  It is NULL if no USB host controllers have been detected.
> > 
> > I'm not sure if we even want to call grub_term_register_input() if no
> > USB keyboard is present.
> What if a keyboard is not present, but plugged in later?

If we add support for USB hotplug, then we'll take care of it.  I don't
think GRUB will support interrupts, but it may get support for timers
that would rescan the USB tree periodically.

When USB hotplug is not supported, it doesn't really matter if
terminal_input.usb_keyboard succeeds of fails in absence of a USB

By the way, we need to handle the case of multiple keyboards.  That
would automatically take care of the zero keyboards.

It looks like the current code can match non-keyboards.

For my keyboard, "lsusb -v" gives:

  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None

The existing code doesn't check interfaces.

Pavel Roskin

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