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H A Dhcd-ehci.h80826240 Sat Nov 17 05:47:17 CST 2012 Hans de Goede <hdegoede@redhat.com> ehci: Lower timer freq when the periodic schedule is idle

Lower the timer freq if no iso schedule packets complete for 64 frames in
a row.

We can safely do this, without adding latency, because:
1) If there is isoc traffic this will never trigger
2) For async handled interrupt packets (only usb-host), the completion handler
will immediately schedule the frame_timer from a bh
3) All devices using NAK to signal no data for interrupt endpoints now use
wakeup, which will immediately schedule the frame_timer from a bh

The advantage of this is that when we only have interrupt packets in the
periodic schedule, async_stepdown can do its work and significantly lower
the frequency at which the frame_timer runs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
H A Dhcd-ehci.c80826240 Sat Nov 17 05:47:17 CST 2012 Hans de Goede <hdegoede@redhat.com> ehci: Lower timer freq when the periodic schedule is idle

Lower the timer freq if no iso schedule packets complete for 64 frames in
a row.

We can safely do this, without adding latency, because:
1) If there is isoc traffic this will never trigger
2) For async handled interrupt packets (only usb-host), the completion handler
will immediately schedule the frame_timer from a bh
3) All devices using NAK to signal no data for interrupt endpoints now use
wakeup, which will immediately schedule the frame_timer from a bh

The advantage of this is that when we only have interrupt packets in the
periodic schedule, async_stepdown can do its work and significantly lower
the frequency at which the frame_timer runs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>