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authorAlan Stern <stern@rowland.harvard.edu>2010-01-08 11:17:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-01-20 15:24:34 -0800
commit1b9a38bfa6e664ff02511314f5586d711c83cc91 (patch)
treef58800f54386050429bb0f3a203ec012a2c153b9
parentacbe2febe71abb2360b008e9ab3ee5c44169f78c (diff)
downloadlinux-1b9a38bfa6e664ff02511314f5586d711c83cc91.tar.gz
USB: EHCI: fix handling of unusual interrupt intervals
This patch (as1320) fixes two problems related to interrupt-URB scheduling in ehci-hcd. URBs with an interval of 2 or 4 microframes aren't handled. For the time being, the patch reduces to interval to 1 uframe. URBs are constrained to have an interval no larger than 1024 frames by usb_submit_urb(). But some EHCI controllers allow use of a schedule as short as 256 frames; for these controllers we may have to decrease the interval to the actual schedule length. The second problem isn't very significant since few devices expose interrupt endpoints with an interval larger than 256 frames. But the first problem is critical; it will prevent the kernel from working with devices having interrupt intervals of 2 or 4 uframes. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable <stable@kernel.org> Tested-by: Glynn Farrow <farrowg@sg.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/ehci-q.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index a427d3b0063..89521775c56 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -849,9 +849,10 @@ qh_make (
* But interval 1 scheduling is simpler, and
* includes high bandwidth.
*/
- dbg ("intr period %d uframes, NYET!",
- urb->interval);
- goto done;
+ urb->interval = 1;
+ } else if (qh->period > ehci->periodic_size) {
+ qh->period = ehci->periodic_size;
+ urb->interval = qh->period << 3;
}
} else {
int think_time;
@@ -874,6 +875,10 @@ qh_make (
usb_calc_bus_time (urb->dev->speed,
is_input, 0, max_packet (maxp)));
qh->period = urb->interval;
+ if (qh->period > ehci->periodic_size) {
+ qh->period = ehci->periodic_size;
+ urb->interval = qh->period;
+ }
}
}