diff options
| author |   Ming Lei <ming.lei@canonical.com> | 2012-05-19 23:11:19 +0800 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-05-19 09:31:29 -0700 |
| commit | 1c01f1d9a603ecf1744ae2d1a015c4b27c2b9fa0 (patch) | |
| tree | c8a945d9c09d055c24ebe3780853ed5a8852a11e /drivers/usb/host/ehci-hcd.c | |
| parent | USB: Remove races in devio.c (diff) | |
| download | linux-dev-1c01f1d9a603ecf1744ae2d1a015c4b27c2b9fa0.tar.xz linux-dev-1c01f1d9a603ecf1744ae2d1a015c4b27c2b9fa0.zip | |
USB: EHCI: fix command register configuration lost problem
The 3d9545cc375d117554a9b35dfddadf9189c62775(EHCI: maintain the
ehci->command value properly) introducs one command register
configuration lost problem by the below line in ehci_reset:
ehci->command = ehci_readl(ehci, &ehci->regs->command);
After writting RESET into command register, it is restored to
its default value per EHCI spec[1], so the previous configuration
will be lost, and may introduce some problems reported recently:
- imx51 Babbage board detect usb hub failed[2], reported
by Richard Zhao.
- mouse and keyboard hangs in linux-next found by
Dan Carpenter and Greg-KH.
So this patch just removes the line to fix these problems, and
keep configurating command register consistent as before the commit
3d9545cc(EHCI: maintain the ehci->command value properly).
[1], 4.1 Host Controller Initialization of EHCI Specification 1.0
[2], failed dmesg log:
usb 1-1: new high-speed USB device number 2 using mxc-ehci
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 7 ports detected
mxc-ehci mxc-ehci.1: fatal error
mxc-ehci mxc-ehci.1: HC died; cleaning up
mxc-ehci mxc-ehci.1: force halt; handshake f5780344 00004000 00004000 -> -110
mxc-ehci mxc-ehci.1: HC died; cleaning up
usb 1-1: USB disconnect, device number 2
Reported-by: Richard Zhao <richard.zhao@freescale.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Chen Peter-B29397 <B29397@freescale.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-hcd.c')
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index f644ba9529ed..5597e6099592 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -352,7 +352,6 @@ static int ehci_reset (struct ehci_hcd *ehci) if (ehci->debug) dbgp_external_startup(); - ehci->command = ehci_readl(ehci, &ehci->regs->command); ehci->port_c_suspend = ehci->suspended_ports = ehci->resuming_ports = 0; return retval; |