Re: USB polling (75% done)

On Tue, Jul 21, 2009 at 5:20 AM, Hans Petter Selasky<hselasky_at_c2i.net> wrote:
> On Monday 20 July 2009 23:51:41 Alfred Perlstein wrote:
>> * Hans Petter Selasky <hselasky_at_c2i.net> [090715 13:37] wrote:
>> > Hi,
>> >
>> > I've added minimal polling support to the USB P4 repository now. Patch
>> > can be found here:
>> >
>> > http://perforce.freebsd.org/chv.cgi?CH=166148
>> >
>> > Dumping core to USB disk: Tested and works.
>> >
>> > Using USB keyboard in KDB: Does not work because Giant is not locked when
>> > calling into the UKBD's get char routine. UKBD is Giant locked. Someone
>> > familiar with the keyboard system on FreeBSD please step forward and fix
>> > this so that UKBD gets independent of the Giant mutex.
>>
>> the ukbd driver needs giant?
>
> I think the keyboard mux is under Giant, and does not have any concept about
> mutexes. Most simple solution would be that DDB locks Giant before entering
> into the keyboard code.

as i understand it, keyboard drivers (and kbdmux(4) is a keyboard
driver), can/should not use any locks. period. so whatever calls into
keyboard driver should take care of locking.

thanks,
max