linux/drivers/usb/early
Jason Wessel 56faf0f98f USB: dbgp: EHCI debug controller initialization delays
When using the EHCI host controller as a polled device, a bit more
tolerance is required in terms of delays.  On some 3+ghz systems the
cpu loops were faster than the EHCI device mmio and resulted in the
controller failing to initialize.

On at least one first generation EHCI controller when it was not
operating in interrupt mode, it would fail to report a port change
status, but executing the port reset allowed the debug controller to
work correctly anyway.  This errata causes a one time 300ms delay in
the boot time, where as the typical delay is 1-5ms for an EHCI
controller that does not have this errata.

The debug printk's were fixed to have the correct state messages, and
there was a conversion from using early_printk to printk to avoid
calling the dbgp driver while debugging the initialization.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-23 06:46:38 -07:00
..
ehci-dbgp.c USB: dbgp: EHCI debug controller initialization delays 2009-09-23 06:46:38 -07:00
Makefile USB: ehci,dbgp,early_printk: split ehci debug driver from early_printk.c 2009-09-23 06:46:38 -07:00