From 7cd9c440b3060540775f75afc8cea2e81474f4a6 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Wed, 19 Sep 2012 16:27:26 -0700 Subject: [PATCH] xhci: Intel Panther Point BEI quirk. commit 80fab3b244a22e0ca539d2439bdda50e81e5666f upstream. When a device with an isochronous endpoint is behind a hub plugged into the Intel Panther Point xHCI host controller, and the driver submits multiple frames per URB, the xHCI driver will set the Block Event Interrupt (BEI) flag on all but the last TD for the URB. This causes the host controller to place an event on the event ring, but not send an interrupt. When the last TD for the URB completes, BEI is cleared, and we get an interrupt for the whole URB. However, under a Panther Point xHCI host controller, if the parent hub is unplugged when one or more events from transfers with BEI set are on the event ring, a port status change event is placed on the event ring, but no interrupt is generated. This means URBs stop completing, and the USB device disconnect is not noticed. Something like a USB headset will cause mplayer to hang when the device is disconnected. If another transfer is sent (such as running `sudo lsusb -v`), the next transfer event seems to "unstick" the event ring, the xHCI driver gets an interrupt, and the disconnect is reported to the USB core. The fix is not to use the BEI flag under the Panther Point xHCI host. This will impact power consumption and system responsiveness, because the xHCI driver will receive an interrupt for every frame in all isochronous URBs instead of once per URB. Intel chipset developers confirm that this bug will be hit if the BEI flag is used on any endpoint, not just ones that are behind a hub. This patch should be backported to kernels as old as 3.0, that contain the commit 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support EHCI/xHCI port switching." Signed-off-by: Sarah Sharp Signed-off-by: Ben Hutchings --- drivers/usb/host/xhci-pci.c | 1 + drivers/usb/host/xhci-ring.c | 4 +++- drivers/usb/host/xhci.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index bddcbfca89f1..4ed75722db6b 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -99,6 +99,7 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci) * PPT chipsets. */ xhci->quirks |= XHCI_SPURIOUS_REBOOT; + xhci->quirks |= XHCI_AVOID_BEI; } if (pdev->vendor == PCI_VENDOR_ID_ETRON && pdev->device == PCI_DEVICE_ID_ASROCK_P67) { diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 2e3d46c8d635..dff89ae37dc1 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3467,7 +3467,9 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags, } else { td->last_trb = ep_ring->enqueue; field |= TRB_IOC; - if (xhci->hci_version == 0x100) { + if (xhci->hci_version == 0x100 && + !(xhci->quirks & + XHCI_AVOID_BEI)) { /* Set BEI bit except for the last td */ if (i < num_tds - 1) field |= TRB_BEI; diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 9b12b6c1ffc6..cc368c2ba924 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1488,6 +1488,7 @@ struct xhci_hcd { #define XHCI_TRUST_TX_LENGTH (1 << 10) #define XHCI_SPURIOUS_REBOOT (1 << 13) #define XHCI_COMP_MODE_QUIRK (1 << 14) +#define XHCI_AVOID_BEI (1 << 15) unsigned int num_active_eps; unsigned int limit_active_eps; /* There are two roothubs to keep track of bus suspend info for */ -- 2.39.5