On Wed, Jun 18, 2003 at 06:29:05PM -0700, Matthew Dharm wrote: > On Wed, Jun 18, 2003 at 05:32:25PM -0700, Greg KH wrote: > > On Wed, Jun 18, 2003 at 03:11:12PM -0400, Alan Stern wrote: > > > Greg: > > > > > > As a result of a recently-applied change, there are two new subclass and > > > protocol codes for the usb-storage unusual_devs.h file. The codes are > > > US_SC_DEVICE and US_PR_DEVICE; their meaning is that the driver should use > > > whatever value the device supplies instead of overriding it. > > > > But isn't the entry usually needed to override one of the values in the > > first place? > > > > I'm sorry, but I'm still confused, a simple example might be best to > > help me out. > > 'Usually' is a word I do not like. Some of the time, one of these values > needs to be overriden. Sometimes it does not. If the device only needs > flags (a common condition), then you override is actually needed. > > Imagine a device that properly announces class/subclass/protocol of > 0x8/0x6/0x50 -- but chokes on the START_STOP command. > > (Aside: This is a contrived example, as we fixed the START_STOP problem > upstream, but for a long time this was a very real situation.) > > The entry would (in the past) be formulated with US_PR_BULK and US_SC_SCSI > and list US_FL_START_STOP. > > Now, the entry would read US_PR_DEVICE, US_SC_DEVICE, US_FL_START_STOP. > > As a second example, consider a device that announces 0xff/0xff/0xff -- yet > actually works with US_PR_BULK and US_SC_UFI (I happen to know that there > are actually devices like this in existance). Their entry under both the > old and new system would use US_PR_BULK and US_SC_UFI. > > Is that any more clear?
Very much so, thanks for taking the time to explain it to me. thanks, greg k-h ------------------------------------------------------- This SF.Net email is sponsored by: INetU Attention Web Developers & Consultants: Become An INetU Hosting Partner. Refer Dedicated Servers. We Manage Them. You Get 10% Monthly Commission! INetU Dedicated Managed Hosting http://www.inetu.net/partner/index.php _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
