diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2012-09-28 22:01:34 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-22 17:57:43 +0200 |
| commit | 98cae42d82fe9c9e2b5dacdf391edaa007e147e5 (patch) | |
| tree | 1fc9be10a439d0557d673ca570b48dce3e56df79 /drivers/usb/host/ehci-sched.c | |
| parent | EHCI: improved logic for isochronous scheduling (diff) | |
| download | linux-98cae42d82fe9c9e2b5dacdf391edaa007e147e5.tar.xz linux-98cae42d82fe9c9e2b5dacdf391edaa007e147e5.zip | |
EHCI: use the isochronous scheduling threshold
This patch (as1609) changes the way ehci-hcd uses the "Isochronous
Scheduling Threshold" in its calculations. Until now the code has
ignored the threshold except for certain Intel PCI-based controllers.
This violates the EHCI spec.
The new code takes the threshold into account always, removing the
need for the fs_i_thresh quirk flag. In addition it implements the
"full frame cache" setting more efficiently, moving forward only as
far as the next frame boundary instead of always moving forward 8
microframes.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-sched.c')
| -rw-r--r-- | drivers/usb/host/ehci-sched.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 7eb242f27c00..b764cab2ab9a 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1391,15 +1391,11 @@ iso_stream_schedule ( */ if (likely (!list_empty (&stream->td_list))) { - /* For high speed devices, allow scheduling within the - * isochronous scheduling threshold. For full speed devices - * and Intel PCI-based controllers, don't (work around for - * Intel ICH9 bug). - */ - if (!stream->highspeed && ehci->fs_i_thresh) - next = now + ehci->i_thresh; + /* Take the isochronous scheduling threshold into account */ + if (ehci->i_thresh) + next = now + ehci->i_thresh; /* uframe cache */ else - next = now; + next = (now + 2 + 7) & ~0x07; /* full frame cache */ /* * Use ehci->last_iso_frame as the base. There can't be any |