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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2012-05-08 07:32:03 -0700
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2012-05-18 15:42:01 -0700
commitdbc33303e457bc9d9179d628951e6b7c7a3f6056 (patch)
tree4c0c1daf3895f65a65e7714a5f0e3e3ea7e12f81 /drivers/usb/host/xhci-mem.c
parent4b2665418c81c87e7a46df690a443b3d5ac5b088 (diff)
downloadop-kernel-dev-dbc33303e457bc9d9179d628951e6b7c7a3f6056.zip
op-kernel-dev-dbc33303e457bc9d9179d628951e6b7c7a3f6056.tar.gz
xhci: Reserve one command for USB3 LPM disable.
We want to do everything we can to ensure that USB 3.0 Link Power Management (LPM) can be disabled when it is enabled. If LPM can't be disabled, we can't suspend USB 3.0 devices, or reset them. To make sure we can submit the command to disable LPM, allocate a command in the xhci_hcd structure, and reserve one TRB on the command ring. We only need one command per xHCI driver instance, because LPM is only disabled or enabled while the USB core is holding the bandwidth_mutex that is shared between the xHCI USB 2.0 and USB 3.0 roothubs. The bandwidth_mutex will be held until the command completes, or times out. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Diffstat (limited to 'drivers/usb/host/xhci-mem.c')
-rw-r--r--drivers/usb/host/xhci-mem.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 497ed77..ec4338e 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1815,6 +1815,8 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
xhci->event_ring = NULL;
xhci_dbg(xhci, "Freed event ring\n");
+ if (xhci->lpm_command)
+ xhci_free_command(xhci, xhci->lpm_command);
xhci->cmd_ring_reserved_trbs = 0;
if (xhci->cmd_ring)
xhci_ring_free(xhci, xhci->cmd_ring);
@@ -2377,6 +2379,16 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
xhci_dbg_cmd_ptrs(xhci);
+ xhci->lpm_command = xhci_alloc_command(xhci, true, true, flags);
+ if (!xhci->lpm_command)
+ goto fail;
+
+ /* Reserve one command ring TRB for disabling LPM.
+ * Since the USB core grabs the shared usb_bus bandwidth mutex before
+ * disabling LPM, we only need to reserve one TRB for all devices.
+ */
+ xhci->cmd_ring_reserved_trbs++;
+
val = xhci_readl(xhci, &xhci->cap_regs->db_off);
val &= DBOFF_MASK;
xhci_dbg(xhci, "// Doorbell array is located at offset 0x%x"
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