On 7/15/07, Hans Petter Selasky <[EMAIL PROTECTED]> wrote:
>
> 2) For the host, how does it know that the buffer data is still correct if
> the buffer is not cleared?
Clear stall should only clear the data toggle!
You need a second control command to reset the buffers and/or the protocol!
>
> 2) What cause the stall to happen in the first place?
It is either a wrong data-toggle bit or a protocol error. The device can send
stall at any time!
Thanks a lot for the detailed explanation.
If it is a protocol error for the control endpoint 0 (EP0), the host will not
need to send a clear stall feature request to EP0. Even if it is sent
(shall we consider it a bug of the USB stack if that is the case?),
the current PICkit 2 firmware will filter out it and ignore it.
So I think we can narrow it down to the wrong data-toggle bit. I will
dig further. I'd like to convince the PICKit 2 firmware developer
that something is wrong even though it is now working under
FreeBSD. Could we see the reason for the stall from the following
USB log?
===[mcuee] ~ # dmesg | grep ugen
ugen0: <Microchip Technology Inc. PICkit 2 Microcontroller Programmer,
class 0/0, rev 2.00/0.01, addr 126>
ugenopen: flag=1, mode=8192
ugenioctl: cmd=40125569
ugenclose: flag=1, mode=8192
ugenopen: flag=3, mode=8192
ugenioctl: cmd=80045572
ugenioctl: cmd=c018556f
ugenioctl: cmd=80045572
ugenioctl: cmd=c018556f
ugenioctl: cmd=80045572
ugenioctl: cmd=c018556f
ugenioctl: cmd=80045572
ugenioctl: cmd=c018556f
ugenclose: flag=3, mode=8192
ugenopen: flag=3, mode=8192
ugenioctl: cmd=80045565
ugen_set_config: configno 1, sc=0xc31ad800
ugenclose: flag=0, mode=0
ugenopen: flag=3, mode=8192
ugenioctl: cmd=80045572
ugenwrite:
ugenwrite: transferred 64 bytes
ugenioctl: cmd=80045572
ugenwrite:
ugenwrite: transferred 64 bytes
ugenioctl: cmd=80045572
ugenioctl: cmd=80045571
ugenread:
ugen_open_pipe_read: interrupt open done
ugenclose: flag=3, mode=8192
ugenclose: flag=3, mode=8192
On 7/8/07, M. Warner Losh <[EMAIL PROTECTED]> wrote:
: > Why FreeBSD sends out the clear stall feature request for PICKit 2?
:
: Therefore it must be a 'protocol stall' and FreeBSD does not need to
: send a clear feature request for the endpoint 0 to PICkit 2.
I need to look it up, but I believe that a clear endpoint stall also
resets the toggle, and that was the bug that was tracked down.
Remind me when is this clear endpoint stall sent? In 7.x we don't
send one on pipe open unless the device is quirked to require one. On
RELENG_6, at least as of today, we never send one on the open.
I am using the alternative stack from Hans and 6.2 Stable version. So
maybe there is a difference here.
Xiaofan
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