From 4db62cb8b0f02da23045deaf20c51f1195d63a1c Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Fri, 16 Mar 2012 13:09:39 -0700 Subject: [PATCH] xhci: Don't write zeroed pointers to xHC registers. BugLink: http://bugs.launchpad.net/bugs/987337 commit 159e1fcc9a60fc7daba23ee8fcdb99799de3fe84 upstream. When xhci_mem_cleanup() is called, we can't be sure if the xHC is actually halted. We can ask the xHC to halt by writing to the RUN bit in the command register, but that might timeout due to a HW hang. If the host controller is still running, we should not write zeroed values to the event ring dequeue pointers or base tables, the DCBAA pointers, or the command ring pointers. Eric Fu reports his VIA VL800 host accesses the event ring pointers after a failed register restore on resume from suspend. The hypothesis is that the host never actually halted before the register write to change the event ring pointer to zero. Remove all writes of zeroed values to pointer registers in xhci_mem_cleanup(). Instead, make all callers of the function reset the host controller first, which will reset those registers to zero. xhci_mem_init() is the only caller that doesn't first halt and reset the host controller before calling xhci_mem_cleanup(). This should be backported to kernels as old as 2.6.32. Signed-off-by: Sarah Sharp Tested-by: Elric Fu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- drivers/usb/host/xhci-mem.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index c69cf54..01c3800 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1704,11 +1704,6 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci) int i; /* Free the Event Ring Segment Table and the actual Event Ring */ - if (xhci->ir_set) { - xhci_writel(xhci, 0, &xhci->ir_set->erst_size); - xhci_write_64(xhci, 0, &xhci->ir_set->erst_base); - xhci_write_64(xhci, 0, &xhci->ir_set->erst_dequeue); - } size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries); if (xhci->erst.entries) dma_free_coherent(&pdev->dev, size, @@ -1720,7 +1715,6 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci) xhci->event_ring = NULL; xhci_dbg(xhci, "Freed event ring\n"); - xhci_write_64(xhci, 0, &xhci->op_regs->cmd_ring); if (xhci->cmd_ring) xhci_ring_free(xhci, xhci->cmd_ring); xhci->cmd_ring = NULL; @@ -1749,7 +1743,6 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci) xhci->medium_streams_pool = NULL; xhci_dbg(xhci, "Freed medium stream array pool\n"); - xhci_write_64(xhci, 0, &xhci->op_regs->dcbaa_ptr); if (xhci->dcbaa) dma_free_coherent(&pdev->dev, sizeof(*xhci->dcbaa), xhci->dcbaa, xhci->dcbaa->dma); @@ -2358,6 +2351,8 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags) fail: xhci_warn(xhci, "Couldn't initialize memory\n"); + xhci_halt(xhci); + xhci_reset(xhci); xhci_mem_cleanup(xhci); return -ENOMEM; } -- 1.7.10.4