path: root/drivers
diff options
authorAlan Stern <stern@rowland.harvard.edu>2011-07-19 14:01:23 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:23:14 -0700
commit38e6bb765aaa79257f99b7a9b8ba6d3d034d73c5 (patch)
tree13a6da3a54adb5f78d4b1659f372126bf2ad3c1a /drivers
parent108786ae74b65d83e4cd9d43bb53cfa75048572f (diff)
EHCI: fix direction handling for interrupt data toggles
commit e04f5f7e423018bcec84c11af2058cdce87816f3 upstream. This patch (as1480) fixes a rather obscure bug in ehci-hcd. The qh_update() routine needs to know the number and direction of the endpoint corresponding to its QH argument. The number can be taken directly from the QH data structure, but the direction isn't stored there. The direction is taken instead from the first qTD linked to the QH. However, it turns out that for interrupt transfers, qh_update() gets called before the qTDs are linked to the QH. As a result, qh_update() computes a bogus direction value, which messes up the endpoint toggle handling. Under the right combination of circumstances this causes usb_reset_endpoint() not to work correctly, which causes packets to be dropped and communications to fail. Now, it's silly for the QH structure not to have direct access to all the descriptor information for the corresponding endpoint. Ultimately it may get a pointer to the usb_host_endpoint structure; for now, adding a copy of the direction flag solves the immediate problem. This allows the Spyder2 color-calibration system (a low-speed USB device that sends all its interrupt data packets with the toggle set to 0 and hance requires constant use of usb_reset_endpoint) to work when connected through a high-speed hub. Thanks to Graeme Gill for supplying the hardware that allowed me to track down this bug. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Graeme Gill <graeme@argyllcms.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
2 files changed, 3 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index f51345f6619f..0ee5b4b791b4 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -103,7 +103,7 @@ qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
if (!(hw->hw_info1 & cpu_to_hc32(ehci, 1 << 14))) {
unsigned is_out, epnum;
- is_out = !(qtd->hw_token & cpu_to_hc32(ehci, 1 << 8));
+ is_out = qh->is_out;
epnum = (hc32_to_cpup(ehci, &hw->hw_info1) >> 8) & 0x0f;
if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
@@ -923,6 +923,7 @@ done:
hw = qh->hw;
hw->hw_info1 = cpu_to_hc32(ehci, info1);
hw->hw_info2 = cpu_to_hc32(ehci, info2);
+ qh->is_out = !is_input;
usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
qh_refresh (ehci, qh);
return qh;
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index ac321ef589f6..5b3ca7417804 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -366,6 +366,7 @@ struct ehci_qh {
#define NO_FRAME ((unsigned short)~0) /* pick new start */
struct usb_device *dev; /* access to TT */
+ unsigned is_out:1; /* bulk or intr OUT */
unsigned clearing_tt:1; /* Clear-TT-Buf in progress */