[Dev] Anyone know what this is?

Guodong Xu guodong.xu at linaro.org
Mon Apr 20 01:18:00 UTC 2015


On 18 April 2015 at 02:39, Jorge Ramirez-Ortiz <
jorge.ramirez-ortiz at linaro.org> wrote:

> On 04/17/2015 10:01 AM, Daniel Thompson wrote:
> > On 17/04/15 12:25, Jorge Ramirez-Ortiz wrote:
> >> On 04/17/2015 04:37 AM, Daniel Thompson wrote:
> >>> On 17/04/15 02:58, Jorge Ramirez-Ortiz wrote:
> >>>> On 04/16/2015 08:58 PM, Scott Bambrough wrote:
> >>>>> BT works, I get this on 258, 260 -- hadn't seen it before.
> >>>>
> >>>> it means that BT is taken longer to initialize - ie: user space (UIM)
> is
> >>>> taking
> >>>> longer to run measured from the time the btwilink.ko is modprobed by
> udev.
> >>>
> >>> Forgive my interfering but I'm not sure all this comes from userspace
> >>> (although the cause could be in userspace).
> >>
> >> please everyone more than welcome to interfere.
> >>>
> >>> I had a look at the ti driver code earlier in the week and first four
> messages
> >>> looked to me like a failure to get the TI device into firmware loading
> mode.
> >>
> >> yes - well kind of.
> >>
> >> when the driver is loaded, st_kim_start waits for the line discipline
> to be
> >> installed.
> >> [0]
> https://github.com/96boards/linux/blob/hikey/drivers/misc/ti-st/st_kim.c#L461
> >>
> >>
> >> the completion is waiting for is usermode opening the tty[1] and the
> completion
> >> being executed (from st_tty_open) [2]
> >> [1] https://github.com/96boards/uim/blob/master/uim.c#L289
> >> [2]
> >>
> https://github.com/96boards/linux/blob/hikey/drivers/misc/ti-st/st_core.c#L702
> >>
> >> once opened, the line discipline is installed and the firmarware
> version present
> >> in the device is read at dhe default settings (115kbps)
> >> The driver reads "TIInit_11.8.32.bts" - meaning the that device is
> accessible
> >> and healthy.
> >>
> >> After this has happened, usermode then takes control (UIM) and changes
> the baud
> >> rate command in the firmware to the value presented by the device tree
> to the
> >> user via sysfs.
> >> https://github.com/96boards/uim/blob/master/uim.c#L356
> >>
> >> this is done by sending 0xFF36 opcode (see here):
> >> https://github.com/96boards/uim/blob/master/uim.c#L356
> >>
> >> and I think this is pretty much what is happening.
> >
> > Thanks for the detailed reply.
> >
> > As you probably guessed I could see the tiny details but not the bigger
> > picture. Your e-mail is very clear.
> >
>
> I had to review the BT stack a few months ago so I kind of remembered it a
> little.
> btw I am not saying there is not a problem somewhere: just that I dont
> think it
> is BT related and that the messages look OK.
>
> However the fact that UIM is running late is probably not a good sign
> (since the
> UIM hasnt changed in a while it must be something else)
>

User space starts up much slower, that's one regression in build #258. And
it has been fixed in build #260, see for details.
https://github.com/96boards/bugs/issues/47

-Guodong


> if the problem continues to happen I can spend some time tracing it.
>
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