From: Wolfgang Grandegger <wg@grandegger.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] USB: relax usbcore reset timings
Date: Wed, 21 Dec 2011 11:01:09 +0100 [thread overview]
Message-ID: <4EF1AE65.2070208@grandegger.com> (raw)
From: Wolfgang Grandegger <wg@denx.de>
Following the corresponding Linux code, this patch relaxes reset timings
waiting at least 100ms after power to the ports. There are some reports
that it helps make enumeration work better on some high speed devices.
Furthermore, the wait is only done once after power has been enabled
on all ports.
CC: Remy Bohmer <linux@bohmer.net>
CC: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Wolfgang Grandegger <wg@denx.de>
---
common/usb.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/common/usb.c b/common/usb.c
index 63a11c8..d13dab8 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -1035,6 +1035,7 @@ static void usb_hub_power_on(struct usb_hub_device *hub)
{
int i;
struct usb_device *dev;
+ unsigned pgood_delay = hub->desc.bPwrOn2PwrGood * 2;
dev = hub->pusb_dev;
/* Enable power to the ports */
@@ -1042,8 +1043,10 @@ static void usb_hub_power_on(struct usb_hub_device *hub)
for (i = 0; i < dev->maxchild; i++) {
usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
USB_HUB_PRINTF("port %d returns %lX\n", i + 1, dev->status);
- wait_ms(hub->desc.bPwrOn2PwrGood * 2);
}
+
+ /* Wait at least 100 msec for power to become stable */
+ wait_ms(max(pgood_delay, (unsigned)100));
}
void usb_hub_reset(void)
--
1.7.6.4
next reply other threads:[~2011-12-21 10:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 10:01 Wolfgang Grandegger [this message]
2012-01-15 19:49 ` [U-Boot] [PATCH] USB: relax usbcore reset timings Remy Bohmer
2012-02-26 23:10 ` Marek Vasut
2012-02-27 8:09 ` Wolfgang Grandegger
2012-02-27 13:41 ` Marek Vasut
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