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| author | Alan Stern <stern@rowland.harvard.edu> | 2013-03-22 13:31:58 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-25 13:36:32 -0700 |
| commit | 214ac7a0771d95d2f66d01bca5afeb2c9e8ac3c8 (patch) | |
| tree | 11355668006ea8d2c2ebbb25770d11a8d397cb5b /drivers/usb/host/ehci-hcd.c | |
| parent | 6e018751a35f6ef7ad04eb8006b5886b6a7c47f5 (diff) | |
| download | lwn-214ac7a0771d95d2f66d01bca5afeb2c9e8ac3c8.tar.gz lwn-214ac7a0771d95d2f66d01bca5afeb2c9e8ac3c8.zip | |
USB: EHCI: improve end_unlink_async()
This patch (as1665) changes the way ehci-hcd's end_unlink_async()
routine works in order to avoid recursive execution and to be more
efficient:
Now when an IAA cycle ends, a new one gets started up right
away (if it is needed) instead of waiting until the
just-unlinked QH has been processed.
The async_iaa list is renamed to async_idle, which better
expresses its new purpose: It is now the list of QHs which are
now completely idle and are waiting to be processed by
end_unlink_async().
A new flag is added to track whether an IAA cycle is in
progress, because the list formerly known as async_iaa no
longer stores the QHs waiting for the IAA to finish.
The decision about how many QHs to process when an IAA cycle
ends is now made at the end of the cycle, when we know the
current state of the hardware, rather than at the beginning.
This means a bunch of logic got moved from start_iaa_cycle()
to end_unlink_async().
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-hcd.c')
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index b32323ca07d3..037a4729d549 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -483,7 +483,7 @@ static int ehci_init(struct usb_hcd *hcd) */ ehci->periodic_size = DEFAULT_I_TDPS; INIT_LIST_HEAD(&ehci->async_unlink); - INIT_LIST_HEAD(&ehci->async_iaa); + INIT_LIST_HEAD(&ehci->async_idle); INIT_LIST_HEAD(&ehci->intr_unlink); INIT_LIST_HEAD(&ehci->intr_qh_list); INIT_LIST_HEAD(&ehci->cached_itd_list); @@ -752,7 +752,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) /* guard against (alleged) silicon errata */ if (cmd & CMD_IAAD) ehci_dbg(ehci, "IAA with IAAD still set?\n"); - if (!list_empty(&ehci->async_iaa)) + if (ehci->iaa_in_progress) COUNT(ehci->stats.iaa); end_unlink_async(ehci); } |