Hi all,
I have been trying to fix a problem related to usb, with the help of the
usb-dev list. Plugging in a usb device hangs my computer when bandwidth
reclamation (fsbr) is turned on in the uhci-hcd driver.
I have found though, that when an interrupt is triggered by plugging in
a usb device, the timer_interrupt() function in arch/i386/kernel/time.c
is reached, and the computer hangs in mark_offset_tsc() in
timers/timer_tsc.c. I removed the call to this function in
timer_interrupt() and then usb worked as normal. I'm hoping there's a
better way to get usb working than this though! This doesn't happen when
fsbr is switched off.
The computer has a Crusoe TM5400 cpu and a VIA VT82C686A controller.
Thanks,
Malcolm.
I wrote:
> I have been trying to fix a problem related to usb, with the help of the
> usb-dev list. Plugging in a usb device hangs my computer when bandwidth
> reclamation (fsbr) is turned on in the uhci-hcd driver.
>
> I have found though, that when an interrupt is triggered by plugging in
> a usb device, the timer_interrupt() function in arch/i386/kernel/time.c
> is reached, and the computer hangs in mark_offset_tsc() in
> timers/timer_tsc.c. I removed the call to this function in
> timer_interrupt() and then usb worked as normal. I'm hoping there's a
> better way to get usb working than this though! This doesn't happen when
> fsbr is switched off.
>
> The computer has a Crusoe TM5400 cpu and a VIA VT82C686A controller.
I've been trying to work out what goes wrong in mark_offset_tsc() and
found that it's just the outb_p() & inb_p() calls that are causing the
problem. I found a thread relating to this,
http://www.ussg.iu.edu/hypermail/linux/kernel/0309.2/1039.html, and
tried the line:
#define __SLOW_DOWN_IO__ ""
which also allowed usb to work normally. Since this is just avoiding the
read or write to port 0x80, is this a sign of having dodgy hardware? The
thread doesn't talk about writing to the port as being fatal, even if it
does cause problems for some people.
Anybody got a better fix?
Malcolm.