From: JC Kuo <jckuo@nvidia.com>
To: <mathias.nyman@linux.intel.com>, <gregkh@linuxfoundation.org>,
<thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
<robh@kernel.org>
Cc: <linux-tegra@vger.kernel.org>, <linux-usb@vger.kernel.org>,
<nkristam@nvidia.com>, JC Kuo <jckuo@nvidia.com>
Subject: [PATCH] xhci: tegra: Delay for disabling LFPS detector
Date: Sat, 19 Dec 2020 00:42:34 +0800 [thread overview]
Message-ID: <20201218164234.128762-1-jckuo@nvidia.com> (raw)
Occasionally, we are seeing some SuperSpeed devices resumes right after
being directed to U3. This commits add 500us delay to ensure LFPS
detector is disabled before sending ACK to firmware.
[ 16.099363] tegra-xusb 70090000.usb: entering ELPG
[ 16.104343] tegra-xusb 70090000.usb: 2-1 isn't suspended: 0x0c001203
[ 16.114576] tegra-xusb 70090000.usb: not all ports suspended: -16
[ 16.120789] tegra-xusb 70090000.usb: entering ELPG failed
Signed-off-by: JC Kuo <jckuo@nvidia.com>
---
drivers/usb/host/xhci-tegra.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index 934be1686352..20cdc11f7dc6 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -623,6 +623,12 @@ static void tegra_xusb_mbox_handle(struct tegra_xusb *tegra,
enable);
if (err < 0)
break;
+
+ /*
+ * wait 500us for LFPS detector to be disabled before sending ACK
+ */
+ if (!enable)
+ usleep_range(500, 1000);
}
if (err < 0) {
--
2.25.1
next reply other threads:[~2020-12-18 16:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-18 16:42 JC Kuo [this message]
2020-12-18 16:53 ` [PATCH] xhci: tegra: Delay for disabling LFPS detector Greg KH
2021-01-06 6:05 ` JC Kuo
2021-01-07 9:53 ` Mathias Nyman
2021-01-08 6:32 ` JC Kuo
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