urb function ABORT PIPE

[g***@bergamoblog.it]

hi all,
i found on windows usb sdk a urb function called URB_FUNCTION_ABORT_PIPE ..
do you know why is not implemented on linux usb driver?
Can it be compared with USBDEVFS_CLEAR_HALT urb linux function?
thnx in advance
Kolja




-------------------------------------------------------
This SF.net email is sponsored by: IBM Linux Tutorials.
Become an expert in LINUX or just sharpen your skills. Sign up for IBM's
Free Linux Tutorials. Learn everything from the bash shell to sys admin.
Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click
_______________________________________________
linux-usb-***@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel

[David Brownell]

Post by g***@bergamoblog.it
hi all,
i found on windows usb sdk a urb function called URB_FUNCTION_ABORT_PIPE ..
do you know why is not implemented on linux usb driver?

Interesting. Alan Stern had recently proposed implementing
something that sounds very similar. Linux 2.6 has this
function internal to usbcore, and it'd be useful to expose
it for general use by drivers.

Post by g***@bergamoblog.it
Can it be compared with USBDEVFS_CLEAR_HALT urb linux function?

Not from what I can tell. That's a user-space API, not a
kernel API, but its kernel analogue is usb_clear_halt().
That's used to re-open communications to a bulk or interrupt
endpoint, after they stalled.

Stalling an endpoint shouldn't be the same as canceling pending
requests; it changes hardware state.

- Dave




-------------------------------------------------------
This SF.net email is sponsored by: IBM Linux Tutorials.
Become an expert in LINUX or just sharpen your skills. Sign up for IBM's
Free Linux Tutorials. Learn everything from the bash shell to sys admin.
Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click
_______________________________________________
linux-usb-***@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel

[g***@bergamoblog.it]

Post by David Brownell

Post by g***@bergamoblog.it
hi all,
i found on windows usb sdk a urb function called

URB_FUNCTION_ABORT_PIPE ..

Post by David Brownell

Post by g***@bergamoblog.it
do you know why is not implemented on linux usb driver?

Interesting. Alan Stern had recently proposed implementing
something that sounds very similar. Linux 2.6 has this
function internal to usbcore, and it'd be useful to expose
it for general use by drivers.

I'll check the usbcore.c on linux 2.6 sources to clear me the point.

Post by David Brownell

Post by g***@bergamoblog.it
Can it be compared with USBDEVFS_CLEAR_HALT urb linux function?

Not from what I can tell. That's a user-space API, not a
kernel API, but its kernel analogue is usb_clear_halt().
That's used to re-open communications to a bulk or interrupt
endpoint, after they stalled.

As you described USBDEVS_CLEAR_HALT, i found it very similar to definition
indicated for ABORT_PIPE function.
Here it is (http://www.osr.com/ddk/buses/usbstrct_1e0i.htm)
...
URB_FUNCTION_ABORT_PIPE - Indicates that all outstanding requests for a
pipe should be canceled. If set, the URB is used with _URB_PIPE_REQUST as
the data structure. ...

Post by David Brownell
Stalling an endpoint shouldn't be the same as canceling pending
requests; it changes hardware state.
- Dave

Best
Kolja




-------------------------------------------------------
This SF.net email is sponsored by: IBM Linux Tutorials.
Become an expert in LINUX or just sharpen your skills. Sign up for IBM's
Free Linux Tutorials. Learn everything from the bash shell to sys admin.
Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click
_______________________________________________
linux-usb-***@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel