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Massimiliano Ghilardi
c4766560e4
The MP3/MP4/AVI player "Rockchip ROCK MP3" is seen as a USB disk, but fails if more than 128 sectors (64kB) are sent or requested in a single read or write command, and disconnects from the USB bus. Typical kernel log showing the problem is: usb 3-1: reset high speed USB device using ehci_hcd and address 6 usb 3-1: reset high speed USB device using ehci_hcd and address 6 sd 14:0:0:0: [sdb] Result: hostbyte=0x07 driverbyte=0x00 end_request: I/O error, dev sdb, sector 32 sd 14:0:0:0: [sdb] Result: hostbyte=0x07 driverbyte=0x00 end_request: I/O error, dev sdb, sector 32 usb 3-1: USB disconnect, address 6 This patch works around the device limitation by adding "Rockchip ROCK MP3" to unusual USB devices list and limiting data transfers to 64 sectors (32kB) per command. Tested on 2.6.23-rc5 (amd64). Signed-off-by: Massimiliano Ghilardi <massimiliano.ghilardi@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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.