Subject: usb: xhci: change enumeration scheme to 'new scheme' by default
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Change the default enumeration scheme for xhci attached non-SuperSpeed
devices from:
Reset
SetAddress [xhci address-device BSR = 0]
GetDescriptor(8)
GetDescriptor(18)
...to:
Reset
[xhci address-device BSR = 1]
GetDescriptor(64)
Reset
SetAddress [xhci address-device BSR = 0]
GetDescriptor(18)
...as some devices misbehave when encountering a SetAddress command
prior to GetDescriptor. There are known legacy devices that require
this scheme, but testing has found at least one USB3 device that fails
enumeration when presented with this ordering. For now, follow the ehci
case and enable 'new scheme' by default for non-SuperSpeed devices.
To support this enumeration scheme on xhci the AddressDevice operation
needs to be performed twice. The first instance of the command enables
the HC's device and slot context info for the device, but omits sending
the device a SetAddress command (BSR == block set address request).
Then, after GetDescriptor completes, follow up with the full
AddressDevice+SetAddress operation.
As mentioned before, this ordering of events with USB3 devices causes an
extra state transition to be exposed to xhci. Previously USB3 devices
would transition directly from 'enabled' to 'addressed' and never need
to underrun responses to 'get descriptor'. We do see the 64-byte
descriptor fetch the correct data, but the following 18-byte descriptor
read after the reset gets:
bLength = 0
bDescriptorType = 0
bcdUSB = 0
bDeviceClass = 0
bDeviceSubClass = 0
bDeviceProtocol = 0
bMaxPacketSize0 = 9
instead of:
bLength = 12
bDescriptorType = 1
bcdUSB = 300
bDeviceClass = 0
bDeviceSubClass = 0
bDeviceProtocol = 0
bMaxPacketSize0 = 9
which results in the discovery process looping until falling back to
'old scheme' enumeration.
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reported-by: David Moore <david.moore@xxxxxxxxx>
Suggested-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
Here is the patch again with the changelog clarifications. Alan, I took
your comments to mean acked-by, let me know it that's not the case.
--
Dan
drivers/usb/core/hub.c | 44 ++++++++++++++++++++++++++++++++++++++----
drivers/usb/host/xhci-pci.c | 1 +
drivers/usb/host/xhci-plat.c | 1 +
drivers/usb/host/xhci-ring.c | 6 +++---
drivers/usb/host/xhci.c | 19 ++++++++++++++----
drivers/usb/host/xhci.h | 11 ++++++++++-
include/linux/usb/hcd.h | 2 ++
7 files changed, 72 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c2c5f5adb464..42069ac9c6b2 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2519,6 +2519,21 @@ static unsigned hub_is_wusb(struct usb_hub *hub)
#define HUB_LONG_RESET_TIME 200
#define HUB_RESET_TIMEOUT 800
+/*
+ * "New scheme" enumeration causes an extra state transition to be
+ * exposed to an xhci host and causes USB3 devices to receive control
+ * commands in the default state. This has been seen to cause
+ * enumeration failures, so disable this enumeration scheme for USB3
+ * devices.
+ */
+static bool use_new_scheme(struct usb_device *udev, int retry)
+{
+ if (udev->speed == USB_SPEED_SUPER)
+ return false;
+
+ return USE_NEW_SCHEME(retry);
+}
+
static int hub_port_reset(struct usb_hub *hub, int port1,
struct usb_device *udev, unsigned int delay, bool warm);
@@ -3951,6 +3966,20 @@ static int hub_set_address(struct usb_device *udev, int devnum)
return retval;
}
+static int hub_enable_device(struct usb_device *udev)
+{
+ struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+ if (!hcd->driver->enable_device)
+ return 0;
+ if (udev->state == USB_STATE_ADDRESS)
+ return 0;
+ if (udev->state != USB_STATE_DEFAULT)
+ return -EINVAL;
+
+ return hcd->driver->enable_device(hcd, udev);
+}
+
/* Reset device, (re)assign address, get device descriptor.
* Device connection must be stable, no more debouncing needed.
* Returns device in USB_STATE_ADDRESS, except on error.
@@ -4063,7 +4092,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
* this area, and this is how Linux has done it for ages.
* Change it cautiously.
*
- * NOTE: If USE_NEW_SCHEME() is true we will start by issuing
+ * NOTE: If use_new_scheme() is true we will start by issuing
* a 64-byte GET_DESCRIPTOR request. This is what Windows does,
* so it may help with some non-standards-compliant devices.
* Otherwise we start with SET_ADDRESS and then try to read the
@@ -4071,10 +4100,13 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
* value.
*/
for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
- if (USE_NEW_SCHEME(retry_counter) && !(hcd->driver->flags & HCD_USB3)) {
- struct usb_device_descriptor *buf;
+ struct usb_device_descriptor *buf;
+ bool did_new_scheme = false;
+
+ if (use_new_scheme(udev, retry_counter)) {
int r = 0;
+ did_new_scheme = true;
#define GET_DESCRIPTOR_BUFSIZE 64
buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO);
if (!buf) {
@@ -4082,6 +4114,10 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
continue;
}
+ retval = hub_enable_device(udev);
+ if (retval < 0)
+ goto fail;
+
/* Retry on all errors; some devices are flakey.
* 255 is for WUSB devices, we actually need to use
* 512 (WUSB1.0[4.8.1]).
@@ -4163,7 +4199,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
* - read ep0 maxpacket even for high and low speed,
*/
msleep(10);
- if (USE_NEW_SCHEME(retry_counter) && !(hcd->driver->flags & HCD_USB3))
+ if (did_new_scheme)
break;
}
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 236c3aabe940..96e51949c8b0 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -306,6 +306,7 @@ static const struct hc_driver xhci_pci_hc_driver = {
.check_bandwidth = xhci_check_bandwidth,
.reset_bandwidth = xhci_reset_bandwidth,
.address_device = xhci_address_device,
+ .enable_device = xhci_enable_device,
.update_hub_device = xhci_update_hub_device,
.reset_device = xhci_discover_or_reset_device,
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index d9c169f470d3..5413861ac0f5 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -69,6 +69,7 @@ static const struct hc_driver xhci_plat_xhci_driver = {
.check_bandwidth = xhci_check_bandwidth,
.reset_bandwidth = xhci_reset_bandwidth,
.address_device = xhci_address_device,
+ .enable_device = xhci_enable_device,
.update_hub_device = xhci_update_hub_device,
.reset_device = xhci_discover_or_reset_device,
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 46d7fb8de990..515a21009d7e 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3962,12 +3962,12 @@ int xhci_queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id)
/* Queue an address device command TRB */
int xhci_queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
- u32 slot_id)
+ u32 slot_id, enum xhci_setup_dev setup)
{
return queue_command(xhci, lower_32_bits(in_ctx_ptr),
upper_32_bits(in_ctx_ptr), 0,
- TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id),
- false);
+ TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id)
+ | (setup == SETUP_CONTEXT_ONLY ? TRB_BSR : 0), false);
}
int xhci_queue_vendor_command(struct xhci_hcd *xhci,
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index d05ff362ddc7..b08369ed2f87 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3705,12 +3705,13 @@ disable_slot:
}
/*
- * Issue an Address Device command (which will issue a SetAddress request to
- * the device).
+ * Issue an Address Device command and optionally send a corresponding
+ * SetAddress request to the device.
* We should be protected by the usb_address0_mutex in khubd's hub_port_init, so
* we should only issue and wait on one address command at the same time.
*/
-int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
+static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev,
+ enum xhci_setup_dev setup)
{
unsigned long flags;
int timeleft;
@@ -3769,7 +3770,7 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
spin_lock_irqsave(&xhci->lock, flags);
cmd_trb = xhci_find_next_enqueue(xhci->cmd_ring);
ret = xhci_queue_address_device(xhci, virt_dev->in_ctx->dma,
- udev->slot_id);
+ udev->slot_id, setup);
if (ret) {
spin_unlock_irqrestore(&xhci->lock, flags);
xhci_dbg_trace(xhci, trace_xhci_dbg_address,
@@ -3864,6 +3865,16 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
return 0;
}
+int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
+{
+ return xhci_setup_device(hcd, udev, SETUP_CONTEXT_ADDRESS);
+}
+
+int xhci_enable_device(struct usb_hcd *hcd, struct usb_device *udev)
+{
+ return xhci_setup_device(hcd, udev, SETUP_CONTEXT_ONLY);
+}
+
/*
* Transfer the port index into real index in the HW port status
* registers. Caculate offset between the port's PORTSC register
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 5f9dc1c1b538..e880776151ae 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1096,6 +1096,14 @@ struct xhci_event_cmd {
};
/* flags bitmasks */
+
+/* Address device - disable SetAddress */
+#define TRB_BSR (1<<9)
+enum xhci_setup_dev {
+ SETUP_CONTEXT_ONLY,
+ SETUP_CONTEXT_ADDRESS,
+};
+
/* bits 16:23 are the virtual function ID */
/* bits 24:31 are the slot ID */
#define TRB_TO_SLOT_ID(p) (((p) & (0xff<<24)) >> 24)
@@ -1787,6 +1795,7 @@ int xhci_free_streams(struct usb_hcd *hcd, struct usb_device *udev,
struct usb_host_endpoint **eps, unsigned int num_eps,
gfp_t mem_flags);
int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev);
+int xhci_enable_device(struct usb_hcd *hcd, struct usb_device *udev);
int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev);
int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
struct usb_device *udev, int enable);
@@ -1810,7 +1819,7 @@ int xhci_is_vendor_info_code(struct xhci_hcd *xhci, unsigned int trb_comp_code);
void xhci_ring_cmd_db(struct xhci_hcd *xhci);
int xhci_queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id);
int xhci_queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
- u32 slot_id);
+ u32 slot_id, enum xhci_setup_dev);
int xhci_queue_vendor_command(struct xhci_hcd *xhci,
u32 field1, u32 field2, u32 field3, u32 field4);
int xhci_queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index fc64b6825f5e..21a8a4286063 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -352,6 +352,8 @@ struct hc_driver {
void (*reset_bandwidth)(struct usb_hcd *, struct usb_device *);
/* Returns the hardware-chosen device address */
int (*address_device)(struct usb_hcd *, struct usb_device *udev);
+ /* prepares the hardware to send commands to the device */
+ int (*enable_device)(struct usb_hcd *, struct usb_device *udev);
/* Notifies the HCD after a hub descriptor is fetched.
* Will block.
*/
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