[PATCH] USB: echi-dbgp: increase the controller wait time to come out of halt.

[PATCH] USB: echi-dbgp: increase the controller wait time to come out of halt.

[Colin Ian King]

The default 10 microsecond delay for the controller to come out of
halt in dbgp_ehci_startup is too short, so increase it to 1 millisecond.

This is based on emperical testing on various USB debug ports on
modern machines such as a Lenovo X220i and an Ivybridge development
platform that needed to wait ~450-950 microseconds.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/usb/early/ehci-dbgp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/early/ehci-dbgp.c b/drivers/usb/early/ehci-dbgp.c
index ee0ebac..89dcf15 100644
--- a/drivers/usb/early/ehci-dbgp.c
+++ b/drivers/usb/early/ehci-dbgp.c
@@ -450,7 +450,7 @@ static int dbgp_ehci_startup(void)
 	writel(FLAG_CF, &ehci_regs->configured_flag);
 
 	/* Wait until the controller is no longer halted */
-	loop = 10;
+	loop = 1000;
 	do {
 		status = readl(&ehci_regs->status);
 		if (!(status & STS_HALT))
-- 
1.7.10.4

Re: [PATCH] USB: echi-dbgp: increase the controller wait time to come out of halt.

[Jason Wessel]

On 07/30/2012 10:06 AM, Colin Ian King wrote:
> The default 10 microsecond delay for the controller to come out of
> halt in dbgp_ehci_startup is too short, so increase it to 1 millisecond.
>
> This is based on emperical testing on various USB debug ports on
> modern machines such as a Lenovo X220i and an Ivybridge development
> platform that needed to wait ~450-950 microseconds.

This seems fine to me.

I'll test it, merge it, and add a CC for -stable.

Thanks,
Jason.