[PATCH 1/1] driver,usb: Fix a warning in uhci-hcd driver

Li, Zhen-Hua
2013-04-25T07:12:07Z

This patch is trying to fix this bug on SLES11 SP2:
https://bugzilla.novell.com/show_bug.cgi?id=817035

On a large HP system with 64T memory and 60 logical cpus, when usb
driver inits the iLo Virtual USB Controller, there comes a warning
"Controller not stopped yet!". It is because driver does not wait
enough time. So driver should wait and retry if found controller
not stopped.

Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
Signed-off-by: Tom Vaden <tom.vaden@hp.com>
---
drivers/usb/host/uhci-hcd.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index 4a86b63..d592e22 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -277,6 +277,9 @@ static int global_suspend_mode_is_broken(struct uhci_hcd *uhci)
uhci->global_suspend_mode_is_broken(uhci) : 0;
}

+#define UHCI_SUSPENDRH_RETRY_MAX 10
+#define UHCI_SUSPENDRH_RETRY_DELAY 100
+
static void suspend_rh(struct uhci_hcd *uhci, enum uhci_rh_state new_state)
__releases(uhci->lock)
__acquires(uhci->lock)
@@ -284,6 +287,8 @@ __acquires(uhci->lock)
int auto_stop;
int int_enable, egsm_enable, wakeup_enable;
struct usb_device *rhdev = uhci_to_hcd(uhci)->self.root_hub;
+ int try;
+ u16 stopped;

auto_stop = (new_state == UHCI_RH_AUTO_STOPPED);
dev_dbg(&rhdev->dev, "%s%s\n", __func__,
@@ -355,7 +360,17 @@ __acquires(uhci->lock)
if (uhci->dead)
return;
}
- if (!(uhci_readw(uhci, USBSTS) & USBSTS_HCH))
+
+ for (try = 0; try < UHCI_SUSPENDRH_RETRY_MAX; try++) {
+ /* For some devices, for example, HP iLo usb controller,
+ * we need to wait for more time and retry.
+ */
+ stopped = uhci_readw(uhci, USBSTS) & USBSTS_HCH;
+ if (stopped)
+ break;
+ udelay(UHCI_SUSPENDRH_RETRY_DELAY);
+ }
+ if (!stopped)
dev_warn(uhci_dev(uhci), "Controller not stopped yet!\n");

uhci_get_current_frame_number(uhci);
--
1.7.10.4