ChangeSet 1.2181.4.11, 2005/03/17 17:33:44-08:00, [EMAIL PROTECTED]
[PATCH] USB: ohci zero length control IN transfers
This fixes a longstanding bug in the OHCI driver, inherited from the 2.4
code. It also fixes a related comment in the EHCI driver, which came
when
the EHCI code was first derived from OHCI. (The EHCI code doesn't have
that bug; the comment was effectively "FIXME add bug".)
The bug: control-IN transfers with no data stages have status stages
with
an IN packet (like a control-OUT transfer), instead of using an OUT
packet.
See figure 8-37 of the USB spec. The current code makes trouble with
some
peripheral hardware and zero length IN transfers (scarce in the Real
World).
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
ehci-q.c | 2 +-
ohci-q.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff -Nru a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
--- a/drivers/usb/host/ehci-q.c 2005-03-30 15:06:27 -08:00
+++ b/drivers/usb/host/ehci-q.c 2005-03-30 15:06:27 -08:00
@@ -522,7 +522,7 @@
else
buf = 0;
- // FIXME this 'buf' check break some zlps...
+ /* for zero length DATA stages, STATUS is always IN */
if (!buf || is_input)
token |= (1 /* "in" */ << 8);
/* else it's already initted to "out" pid (0 << 8) */
diff -Nru a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c
--- a/drivers/usb/host/ohci-q.c 2005-03-30 15:06:27 -08:00
+++ b/drivers/usb/host/ohci-q.c 2005-03-30 15:06:27 -08:00
@@ -663,7 +663,7 @@
/* NOTE: mishandles transfers >8K, some >4K */
td_fill (ohci, info, data, data_len, urb, cnt++);
}
- info = is_out
+ info = (is_out || data_len == 0)
? TD_CC | TD_DP_IN | TD_T_DATA1
: TD_CC | TD_DP_OUT | TD_T_DATA1;
td_fill (ohci, info, data, 0, urb, cnt++);
-
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