[SeaBIOS] questions about seabios ohci code

[Qing Pei Wang]

Kevin,
   i had tested the OHCI keyboard, the works but not pretty good as enough.
the reaction time is too long.
So i am trying to learn more about this things.
BTW, seabios/OHCI use count=DIV_ROUND_UP(PIT_TICK_INTERVAL * 1000 * 2,
PIT_TICK_RATE * ms)+1
as the td count. i can not find any document  about that. Where can i find
or some place i missing with OHCI spec?
On Wed, Apr 14, 2010 at 9:22 AM, Kevin O'Connor <kevin at koconnor.net> wrote:

> I'm CC'ing the mailing list.
>
> On Wed, Apr 14, 2010 at 02:04:48AM +0800, Qing Pei Wang wrote:
> > hi kevin,
> >    i am learning the code of seabios/ohci stack followed with OHCI spec.
> I
> > have some question.
>
> Note that the OHCI support has only been tested on a modified qemu - I
> haven't had any reports on real hardware.
>
> > 1) in the function alloc_intr_pipe (usb.c line118)what does the frameexp
> > mean?
>
> It's log2(epdesc->bInterval) - the log of the sampling time (in ms)
> requested by the device.
>
> > 2) how does ohci get the intervals. the code just use epdesc->bInterval,
> how
> > does it init? can pass the parameter from the usb-hid.c?
>
> The epdesc structure is populated by get_device_config() - the config
> read from the device includes the device config, interface
> descriptions, and end point descriptions.
>
> -Kevin
>



-- 
Wang Qing Pei
MSN:wangqingpei at hotmail.com <MSN%3Awangqingpei at hotmail.com>
Gmail:wangqingpei at gmail.com <Gmail%3Awangqingpei at gmail.com>
Phone:86+13426369984
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