When system software decides to power down the xHC with the intent of resuming operation at a later time, it will ask xHC to save the internal state and restore it when resume to correctly recover from a power event. Two bits are used to enable this operation: Save State and Restore State.
xHCI spec 4.23.2 says software should "Set the Controller Save/Restore State flag in the USBCMD register and wait for the Save/Restore State Status flag in the USBSTS register to transition to '0'". However, it does not define how long software should wait for the SSS/RSS bit to transition to 0. Currently the timeout is set to 1ms. There is bug report (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1002697) indicates that the timeout is too short for ASMedia ASM1042 host controller to save/restore the state successfully. Increase the timeout to 10ms helps to resolve the issue. Signed-off-by: Andiry Xu <[email protected]> Cc: Ming Lei <[email protected]> Cc: <[email protected]> --- drivers/usb/host/xhci.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index afdc73e..73e8817 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -795,8 +795,8 @@ int xhci_suspend(struct xhci_hcd *xhci) command = xhci_readl(xhci, &xhci->op_regs->command); command |= CMD_CSS; xhci_writel(xhci, command, &xhci->op_regs->command); - if (handshake(xhci, &xhci->op_regs->status, STS_SAVE, 0, 10*100)) { - xhci_warn(xhci, "WARN: xHC CMD_CSS timeout\n"); + if (handshake(xhci, &xhci->op_regs->status, STS_SAVE, 0, 10 * 1000)) { + xhci_warn(xhci, "WARN: xHC save state timeout\n"); spin_unlock_irq(&xhci->lock); return -ETIMEDOUT; } @@ -848,8 +848,8 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated) command |= CMD_CRS; xhci_writel(xhci, command, &xhci->op_regs->command); if (handshake(xhci, &xhci->op_regs->status, - STS_RESTORE, 0, 10*100)) { - xhci_dbg(xhci, "WARN: xHC CMD_CSS timeout\n"); + STS_RESTORE, 0, 10 * 1000)) { + xhci_warn(xhci, "WARN: xHC restore state timeout\n"); spin_unlock_irq(&xhci->lock); return -ETIMEDOUT; } -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
