Re: how mass storage device cope with unsupported commands?

"JackRain" <hejieming@xxxxxxxxx> · Thu, 29 Jun 2006 22:15:19 +0800

Alan Stern,您好！

	

======= 2006-06-29 11:15:21 您在来信中写道：=======

>Alan Stern,您好！
>
>	    thanks for your reply!
>
>======= 2006-06-29 00:32:58 您在来信中写道：=======
>
>>On Wed, 28 Jun 2006, JackRain wrote:
>>
>>> linux-usb-users，您好！
>>> 
>>> 	      hi,glad to see you again:)
>>> 
>>> 		  i would like to ask a question about ：  how does mass storage device cope with unsupported commands,such as 0x23 etc?
>>
>>Many mass storage devices do support that command.  It is documented in 
>>the UFI specification.
>		  I mean unsupported command is the command which device received from pc host but the device doesn't implement.
>		  so,i want to know the device how to response this situation.
>          
>>> 		  my way is :  refering to mass bulk-only spec.(usbmassbulk_10  6.6.4 command failure),
>>> 
>>> 	      The device shall report this condition by returning a Command Failed status (bCSWStatus = 01h).
>>> 
>>> 		  so,i now try :
>>> 
>>> 			   1) return with sense_data 6th,12th,13th: 0x5,0x24,0x00.
>>
>>You can't return sense data to the host unless the command was REQUEST 
>>SENSE.
>		  I think i was wrong.
>>> 			   2) return CSW with status (0x01) fail.
>>> 
>>>           but it seems from bus hound that ,the USB commnication halt a long time then reset.
>>
>>What mass storage device are you talking about?  Do you have any logs you 
>>can post?

		  because I write the device usb firmware by myself,i print less message only for the software flow chart.

		  now:
		   1)when device get READ_FORMAT_CAPCITY(0x23) command ,stall the bulk-in endpoint. 
       	   2)waitting for ep0setup interrupt,and get the clear_feature request \
			 unstall the endpoint and toggle the DATA pid by disable then enable the bulk-in endpoint (isp1582)
		   3)bulk-in endpoint send a ACK signal to PC;
		   4)then send the CSW to PC to reflect the command status of this unsupported command 
		   5)EP0TX send a ACK signal to PC

		   6) bus reset.
           7)bulk-out endpoint interrypt occurs,read CBW 
		   if command unsupported ,do the same thing 1~5;
		
		   again bus reset.

           if command supported ,it's normal and go on processing SCSI protocol.
		   and I can't see the disk tray icon on windows.
		   but because bus reset ,the device still won't work.
  
           
		   
>		  the procedure is :
>          1)bulk-out endpoint occurs,read endpoint fifo to get CBW
>		  2)decode CBW and found the unsupported command
>		  3)how to react if the command I don't want to implement  ?
>          4)I tried as i told previously but got bus reset.
>  	
>          I want to know the right way:) 
>   	    
>>> 		  another method i have tried is to stall the bulk-in endpoint then wait host __set feature__ and unstall endpoint.
>>> 	
>>> 		  this failed again~
>>> 
>>>           could anyone tell me the correct way ?? thank you very much~
>>
>>According to the specification, you are supposed to stall the bulk-in
>>endpoint (if the Direction bit was set in bmCBWFlags; otherwise you should
>>stall the bulk-out endpoint) and then return CSW status = 1.  When the
>>host then sends a REQUEST SENSE command, you should reply with key = 0x5,
>>ASC = 0x24, ASCQ = 0x00.
>
>		  Shall the endpoint muct be stalled?? 
>
>		  thanks you!
>>Alan Stern
>>
>
>= = = = = = = = = = = = = = = = = = = =
>			
>
>　　　　　　　　致
>礼！
> 
>				 
>　　　　　　　　JackRain
>　　　　　　　　hejieming@xxxxxxxxx
>　　　　　　　　　　2006-06-29
>

= = = = = = = = = = = = = = = = = = = =
			

　　　　　　　　致
礼！
 
				 
　　　　　　　　JackRain
　　　　　　　　hejieming@xxxxxxxxx
　　　　　　　　　　2006-06-29