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| author | Alan Stern <stern@rowland.harvard.edu> | 2010-01-08 11:17:55 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-01-20 15:24:34 -0800 |
| commit | 1b9a38bfa6e664ff02511314f5586d711c83cc91 (patch) | |
| tree | f58800f54386050429bb0f3a203ec012a2c153b9 | |
| parent | acbe2febe71abb2360b008e9ab3ee5c44169f78c (diff) | |
| download | linux-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.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index a427d3b00634..89521775c567 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; + } } } |