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authorAlan Stern <stern@rowland.harvard.edu>2011-07-19 14:01:23 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:36:04 -0700
commit5d45c43ce89dd679ab224d1f97bc676b61d9b417 (patch)
treebd40cfc307efdd121da7cae156f9ba5586471139
parent2f9c13e2cd4603eb61eacd665222a3616ec2c410 (diff)
downloadlwn-5d45c43ce89dd679ab224d1f97bc676b61d9b417.tar.gz
lwn-5d45c43ce89dd679ab224d1f97bc676b61d9b417.zip
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>
-rw-r--r--drivers/usb/host/ehci-q.c3
-rw-r--r--drivers/usb/host/ehci.h1
2 files changed, 3 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 781c573af2e5..9b46a1ee616f 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);
@@ -945,6 +945,7 @@ 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 556c0b48f3ab..e7c406e6243c 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -365,6 +365,7 @@ 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 */
};