diff mbox

[v3] usb: xhci: bInterval quirk for TI TUSB73x0

Message ID 787d6f0f-d69c-ba4a-8892-b3558c005184@ti.com
State Accepted
Commit 69307ccb9ad7ccb653e332de68effdeaaab6907d
Headers show

Commit Message

Roger Quadros March 22, 2017, 11:43 a.m. UTC
As per [1] issue #4,
"The periodic EP scheduler always tries to schedule the EPs
that have large intervals (interval equal to or greater than
128 microframes) into different microframes. So it maintains
an internal counter and increments for each large interval
EP added. When the counter is greater than 128, the scheduler
rejects the new EP. So when the hub re-enumerated 128 times,
it triggers this condition."

This results in Bandwidth error when devices with periodic
endpoints (ISO/INT) having bInterval > 7 are plugged and
unplugged several times on a TUSB73x0 XHCI host.

Workaround this issue by limiting the bInterval to 7
(i.e. interval to 6) for High-speed or faster periodic endpoints.

[1] - http://www.ti.com/lit/er/sllz076/sllz076.pdf

Signed-off-by: Roger Quadros <rogerq@ti.com>

---
v3:
-fixed some more typos in commit message

v2:
-fixed typo in commit message

 drivers/usb/host/xhci-mem.c | 11 +++++++++++
 drivers/usb/host/xhci-pci.c |  3 +++
 drivers/usb/host/xhci.h     |  1 +
 3 files changed, 15 insertions(+)

-- 
2.7.4


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Comments

Mathias Nyman March 22, 2017, 1:06 p.m. UTC | #1
On 22.03.2017 13:43, Roger Quadros wrote:
> As per [1] issue #4,

> "The periodic EP scheduler always tries to schedule the EPs

> that have large intervals (interval equal to or greater than

> 128 microframes) into different microframes. So it maintains

> an internal counter and increments for each large interval

> EP added. When the counter is greater than 128, the scheduler

> rejects the new EP. So when the hub re-enumerated 128 times,

> it triggers this condition."

>

> This results in Bandwidth error when devices with periodic

> endpoints (ISO/INT) having bInterval > 7 are plugged and

> unplugged several times on a TUSB73x0 XHCI host.

>

> Workaround this issue by limiting the bInterval to 7

> (i.e. interval to 6) for High-speed or faster periodic endpoints.

>

> [1] - http://www.ti.com/lit/er/sllz076/sllz076.pdf

>

> Signed-off-by: Roger Quadros <rogerq@ti.com>

> ---


Added to my for-usb-next queue.

Thanks
-Mathias

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diff mbox

Patch

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index ba1853f4..05fb3f6 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1502,6 +1502,17 @@  int xhci_endpoint_init(struct xhci_hcd *xhci,
 	 */
 	max_esit_payload = xhci_get_max_esit_payload(udev, ep);
 	interval = xhci_get_endpoint_interval(udev, ep);
+
+	/* Periodic endpoint bInterval limit quirk */
+	if (usb_endpoint_xfer_int(&ep->desc) ||
+	    usb_endpoint_xfer_isoc(&ep->desc)) {
+		if ((xhci->quirks & XHCI_LIMIT_ENDPOINT_INTERVAL_7) &&
+		    udev->speed >= USB_SPEED_HIGH &&
+		    interval >= 7) {
+			interval = 6;
+		}
+	}
+
 	mult = xhci_get_endpoint_mult(udev, ep);
 	max_packet = usb_endpoint_maxp(&ep->desc);
 	max_burst = xhci_get_endpoint_max_burst(udev, ep);
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index fc99f51..7b86508 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -199,6 +199,9 @@  static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 			pdev->device == 0x1042)
 		xhci->quirks |= XHCI_BROKEN_STREAMS;
 
+	if (pdev->vendor == PCI_VENDOR_ID_TI && pdev->device == 0x8241)
+		xhci->quirks |= XHCI_LIMIT_ENDPOINT_INTERVAL_7;
+
 	if (xhci->quirks & XHCI_RESET_ON_RESUME)
 		xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
 				"QUIRK: Resetting on resume");
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index da3eb69..2496bd6 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1818,6 +1818,7 @@  struct xhci_hcd {
 #define XHCI_MISSING_CAS	(1 << 24)
 /* For controller with a broken Port Disable implementation */
 #define XHCI_BROKEN_PORT_PED	(1 << 25)
+#define XHCI_LIMIT_ENDPOINT_INTERVAL_7	(1 << 26)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;