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BACKPORT: usb: xhci: Skip xhci_reset in xhci_resume if xhci is being removed

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xhci_reset() currently returns -ENODEV if XHCI_STATE_REMOVING is
set, without completing the xhci handshake, unless the reset completes
exceptionally quickly. This behavior causes a regression on Synopsys
DWC3 USB controllers with dual-role capabilities.

Specifically, when a DWC3 controller exits host mode and removes xhci
while a reset is still in progress, and then attempts to configure its
hardware for device mode, the ongoing, incomplete reset leads to
critical register access issues. All register reads return zero, not
just within the xHCI register space (which might be expected during a
reset), but across the entire DWC3 IP block.

This patch addresses the issue by preventing xhci_reset() from being
called in xhci_resume() and bailing out early in the reinit flow when
XHCI_STATE_REMOVING is set.

Cc: stable <stable@kernel.org>
Fixes: 6ccb83d6c4 ("usb: xhci: Implement xhci_handshake_check_state() helper")
Suggested-by: Mathias Nyman <mathias.nyman@intel.com>
Signed-off-by: Roy Luo <royluo@google.com>
Link: https://lore.kernel.org/r/20250522190912.457583-2-royluo@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 425717664
(cherry picked from commit 3eff494f6e17abf932699483f133a708ac0355dc)
[Roy: xhci_resume() function signature changes, no impact]
Change-Id: I859c3c560e64130e5cd67623f9c39dc31b094584
Signed-off-by: Roy Luo <royluo@google.com>
This commit is contained in:
Roy Luo
2025-05-22 19:09:11 +00:00
committed by Todd Kjos
parent 5c72e9faba
commit 5b3ae3bcbe
1 changed files with 4 additions and 1 deletions
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5
drivers/usb/host/xhci.c
View File

@@ -1091,7 +1091,10 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg)
xhci_dbg(xhci, "Stop HCD\n");
xhci_halt(xhci);
xhci_zero_64b_regs(xhci);
retval = xhci_reset(xhci, XHCI_RESET_LONG_USEC);
if (xhci->xhc_state & XHCI_STATE_REMOVING)
retval = -ENODEV;
else
retval = xhci_reset(xhci, XHCI_RESET_LONG_USEC);
spin_unlock_irq(&xhci->lock);
if (retval)
return retval;