xhci: Some Evaluate Context commands must succeed.

The upcoming USB 3.0 Link PM patches will introduce new API to enable
and disable low-power link states.  We must be able to disable LPM in
order to reset a device, or place the device into U3 (device suspend).
Therefore, we need to make sure the Evaluate Context command to disable
the LPM timeouts can't fail due to there being no room on the command
ring.

Introduce a new flag to the function that queues the Evaluate Context
command, command_must_succeed.  This tells the ring handler that a TRB
has already been reserved for the command (by incrementing
xhci->cmd_ring_reserved_trbs), and basically ensures that prepare_ring()
won't fail.  A similar flag was already implemented for the Configure
Endpoint command queuing function.

All functions that currently call xhci_configure_endpoint() to issue an
Evaluate Context command pass "false" for the "must_succeed" parameter,
so this patch should have no effect on current xHCI driver behavior.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index c60617bb8c2e813c38ae7f8c646e7a903d57c9f8..23b4aefd103609bcf91b8341a6758a9fc4c3b618 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3609,12 +3609,12 @@ int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 
 /* Queue an evaluate context command TRB */
 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
-               u32 slot_id)
+               u32 slot_id, bool command_must_succeed)
 {
        return queue_command(xhci, lower_32_bits(in_ctx_ptr),
                        upper_32_bits(in_ctx_ptr), 0,
                        TRB_TYPE(TRB_EVAL_CONTEXT) | SLOT_ID_FOR_TRB(slot_id),
-                       false);
+                       command_must_succeed);
 }
 
 /*

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 16c05c6b5afab9cba3381dc2d7bd75fdc66ade85..05034f346fad5cb3fba70f71d96674118fcb0a59 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -2446,7 +2446,7 @@ static int xhci_configure_endpoint(struct xhci_hcd *xhci,
                                udev->slot_id, must_succeed);
        else
                ret = xhci_queue_evaluate_context(xhci, in_ctx->dma,
-                               udev->slot_id);
+                               udev->slot_id, must_succeed);
        if (ret < 0) {
                if (command)
                        list_del(&command->cmd_list);

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 58d527ccb24a3fc60fc53636086db927aad399bd..59248449b254ac01818306cfc14a413d8bff33d5 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1757,7 +1757,7 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags,
 int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
                u32 slot_id, bool command_must_succeed);
 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
-               u32 slot_id);
+               u32 slot_id, bool command_must_succeed);
 int xhci_queue_reset_ep(struct xhci_hcd *xhci, int slot_id,
                unsigned int ep_index);
 int xhci_queue_reset_device(struct xhci_hcd *xhci, u32 slot_id);