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    USB: dbgp: EHCI debug controller initialization delays · 56faf0f9
    Jason Wessel 提交于
    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: NJason 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: NGreg Kroah-Hartman <gregkh@suse.de>
    56faf0f9
ehci-dbgp.c 17.8 KB