646a384317
This patch does two things for SCM eUSCSI USB-SCSI converters: 1. SCM eUSCSI bridge devices are hard-wired to use SCSI ID 7. On connecting the converter, access to that ID is attempted during the bus scan. Asking the converter to issue INQUIRY commands to itself isn't very polite and wastes time. Set this_id to 7 so __scsi_scan_target() skips it in the scan. 2. Enable multi-LUN support. eUSCSI devices don't support Get Max LUN requests, returning an error (-32). [Different targets could have different numbers of LUNs, so it wouldn't make sense to return a particular value in response to Get Max LUN.] usb_stor_scan_dwork() does this: /* For bulk-only devices, determine the max LUN value */ if (us->protocol == USB_PR_BULK && !(us->fflags & US_FL_SINGLE_LUN)) { mutex_lock(&us->dev_mutex); us->max_lun = usb_stor_Bulk_max_lun(us); mutex_unlock(&us->dev_mutex); It avoids calling usb_stor_Bulk_max_lun() if US_FL_SINGLE_LUN, but not for US_FL_SCM_MULT_TARG. Since usb_stor_Bulk_max_lun() returns 0 in the error case, us->max_lun was always set to 0. [If the user doesn't want multi-LUN support (perhaps there are SCSI devices which respond to commands on all LUNs?), the US_FL_SINGLE_LUN quirk can be specified on the kernel command line.] Signed-off-by: Mark Knibbs <markk@clara.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To understand all the Linux-USB framework, you'll use these resources: * This source code. This is necessarily an evolving work, and includes kerneldoc that should help you get a current overview. ("make pdfdocs", and then look at "usb.pdf" for host side and "gadget.pdf" for peripheral side.) Also, Documentation/usb has more information. * The USB 2.0 specification (from www.usb.org), with supplements such as those for USB OTG and the various device classes. The USB specification has a good overview chapter, and USB peripherals conform to the widely known "Chapter 9". * Chip specifications for USB controllers. Examples include host controllers (on PCs, servers, and more); peripheral controllers (in devices with Linux firmware, like printers or cell phones); and hard-wired peripherals like Ethernet adapters. * Specifications for other protocols implemented by USB peripheral functions. Some are vendor-specific; others are vendor-neutral but just standardized outside of the www.usb.org team. Here is a list of what each subdirectory here is, and what is contained in them. core/ - This is for the core USB host code, including the usbfs files and the hub class driver ("hub_wq"). host/ - This is for USB host controller drivers. This includes UHCI, OHCI, EHCI, and others that might be used with more specialized "embedded" systems. gadget/ - This is for USB peripheral controller drivers and the various gadget drivers which talk to them. Individual USB driver directories. A new driver should be added to the first subdirectory in the list below that it fits into. image/ - This is for still image drivers, like scanners or digital cameras. ../input/ - This is for any driver that uses the input subsystem, like keyboard, mice, touchscreens, tablets, etc. ../media/ - This is for multimedia drivers, like video cameras, radios, and any other drivers that talk to the v4l subsystem. ../net/ - This is for network drivers. serial/ - This is for USB to serial drivers. storage/ - This is for USB mass-storage drivers. class/ - This is for all USB device drivers that do not fit into any of the above categories, and work for a range of USB Class specified devices. misc/ - This is for all USB device drivers that do not fit into any of the above categories.