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[PATCH] USB: EHCI port tweaks

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One change may improve some S1 or S3 resume cases, and the other
seems mostly to explain some strange state "lsusb" would show.
Two fixes:

  - On resume, don't think about resuming any unpowered port, or
    resetting any port with OWNER set to the OHCI/UHCI companion.
    This will make some S1 and S3 resume scenarios work better.

  - PORT_CSC was not being cleared correctly in ehci_hub_status_data.
    This was visible at least through current versions of "lsusb",
    and might have caused some other hub related strangeness.

    The fix addresses all three write-to-clear bits, using the same
    approach that UHCI happens to use:  a mask of bits that are
    cleared in most writes to that port status register.

Original patch seems to have been from from William.Morrow@amd.com
and this version (from David) finishes the write-to-clear changes.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Brownell
2005-08-31 10:55:38 -07:00
committed by Greg Kroah-Hartman
parent 198b95170f
commit 10f6524a8e
3 changed files with 23 additions and 13 deletions
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8
drivers/usb/host/ehci-hcd.c
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@@ -759,12 +759,16 @@ static int ehci_resume (struct usb_hcd *hcd)
if (time_before (jiffies, ehci->next_statechange))
msleep (100);
/* If any port is suspended, we know we can/must resume the HC. */
/* If any port is suspended (or owned by the companion),
* we know we can/must resume the HC (and mustn't reset it).
*/
for (port = HCS_N_PORTS (ehci->hcs_params); port > 0; ) {
u32 status;
port--;
status = readl (&ehci->regs->port_status [port]);
if (status & PORT_SUSPEND) {
if (!(status & PORT_POWER))
continue;
if (status & (PORT_SUSPEND | PORT_OWNER)) {
down (&hcd->self.root_hub->serialize);
retval = ehci_hub_resume (hcd);
up (&hcd->self.root_hub->serialize);