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@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.
- 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.
- 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