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671b4b2ba9
Many cards based on CY7C68300A/B/C use the USB ID 04b4:6830 but only the B and C variants (EZ-USB AT2LP) support the ATA Command Block functionality, according to the data sheets. The A variant (EZ-USB AT2) locks up if ATACB is attempted, until a typical 30 seconds timeout runs out and a USB reset is performed. https://bugs.launchpad.net/bugs/428469 It seems that one way to spot a CY7C68300A (at least where the card manufacturer left Cypress' EEPROM default vaules, against Cypress' recommendations) is to look at the USB string descriptor indices. A http://media.digikey.com/pdf/Data%20Sheets/Cypress%20PDFs/CY7C68300A.pdf B http://www.farnell.com/datasheets/43456.pdf C http://www.cypress.com/?rID=14189 Note that a CY7C68300B/C chip appears as CY7C68300A if it is running in Backward Compatibility Mode, and if ATACB would be supported in this case there is anyway no way to tell which chip it really is. For 5 years my external USB drive has been locking up for half a minute when plugged in and ata_id is run by udev, or anytime hdparm or similar is run on it. Finally looking at the /correct/ datasheet I think I found the reason. I am aware the quirk in this patch is a bit hacky, but the hardware manufacturers haven't made it easy for us. Signed-off-by: Tormod Volden <debian.tormod@gmail.com> Cc: stable <stable@vger.kernel.org> 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 ("khubd").
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.