Re: [PATCH] USB Mass Storage CBI support

["Aleš Nesrsta" <starous@volny.cz>]

Vladimir 'φ-coder/phcoder' Serbinenko wrote: 
> On 09/26/2010 10:11 PM, Aleš Nesrsta wrote:
> > +  grub_uint8_t cbicb[GRUB_USBMS_CBI_CMD_SIZE] =
> > +    { 0x1d, 0x04, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
> > +      0xff, 0xff
> > +    };
> >   
> Could you deblob this?
> Other that this it can be merged into experimental. Be sure to push
> branches/cbi and then merge branches/cbi into experimental

Hi,

I am sorry, but I don't know what is "deblob", my English language
knowledge is unfortunately little bit limited (as you probably noticed
before...)...
(My dictionary says: "blob" is "small amount of a thick liquid"...)

I guess you probably want to explain what the code means and add related
comment (?)

It is CBI specific command "Command Block Reset" which should be used to
reset CBI protocol in "phase error" or similar fatal cases, i.e. it is
something like "Bulk Only Reset" control command.
There is difference between BO and CBI style of device communication
reset:
"Bulk Only Reset" is class-specific request for Bulk Only Mass Storage
devices.
CBI "Command Block Reset" is sent to device as a command block, i.e. as
DATA of CBI class-specific "universal" request ADSC.
(In both cases should be additionally cleared HALT feature on all EPs -
except control EP 0.)

In "USB Mass Storage Class Control/Bulk/Interrupt (CBI) Transport"
specification
(http://www.usb.org/developers/devclass_docs/usb_msc_cbi_1.1.pdf) you
can find "Command Block Reset" in chapter 2.2 Command Block Reset
Protocol, there is part of specification (citation):

"... To issue a Command Block Reset, the host shall use the Non-Data
Command Protocol to transport the command block:
1Dh 04h FFh FFh FFh FFh ...
The device may use the trailing FFh bytes to distinguish the Command
Block Reset from the legacy op 1Dh SEND DIAGNOSTIC command block.
..."

Regards
Ales 
> 
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