Date: Thu, 05 Aug 2004 11:04:43 -0400 From: Chris <chris@tellme3times.com> To: "M. Warner Losh" <imp@bsdimp.com> Cc: freebsd-current@freebsd.org Subject: Re: USB drivers Message-ID: <41124C8B.2060902@tellme3times.com> In-Reply-To: <20040804.212242.112819552.imp@bsdimp.com> References: <4110F5AE.6030403@tellme3times.com> <20040804.212242.112819552.imp@bsdimp.com>
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M. Warner Losh wrote: > >You misunerstand what's actually happening. There's no case in the >tree where two drivers are attached, at the same time, to the same >device node. There's only one set of pointers. However, with USB, >there can be reasons why multiple things can attach to the same >driver. The usb code tries to do smart things for devices that have >multiple configurations. > >With USB and multi-function devices, here's the code that we use: > > /* First try with device specific drivers. */ > probe and attach driver with a config # of -1 (usegeneric = 0) > return if successful > /* Next try with interface drivers. */ > foreach valid configuration > foreach interface > probe and attach driver > /* Finally try the generic driver. */ > probe and attach driver with a config # of -1 (usegeneric = 1) > return if successful > >I'm not familiar with the specific instance of ulpt and unlpt. > > You are right I do not understand. All I know is that when the system boots, at some point a test is done to see if their are USB devices. If devices exist then attach drivers. What I am trying to determine is why my multifunction printer/scanner receives only one of the two drivers. Is it because the printer does not respond properly? Is it because the printer is not defined? I have many questions here. I looked in the following and just see the code for that specific device. It does not test for multifunction devices. I do not see any code that follows the logic above. src/sys/dev/usb/ulpt.c src/sys/dev/usb/uscanner.c src/sys/dev/usb/usbdevs If you can point me in the right direction, or to some documents on USB driver writing I will try to figure this out. Any help would be appreciated. I will get this to work because I need both and the effort required to switch is just not convenient. Chris
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