diff options
Diffstat (limited to 'drivers/tty')
-rw-r--r-- | drivers/tty/hvc/hvc_xen.c | 30 | ||||
-rw-r--r-- | drivers/tty/serdev/core.c | 14 |
2 files changed, 41 insertions, 3 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index 71e0dd2c0ce5..ebaf7500f48f 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -37,6 +37,8 @@ struct xencons_info { struct xenbus_device *xbdev; struct xencons_interface *intf; unsigned int evtchn; + XENCONS_RING_IDX out_cons; + unsigned int out_cons_same; struct hvc_struct *hvc; int irq; int vtermno; @@ -138,6 +140,8 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len) XENCONS_RING_IDX cons, prod; int recv = 0; struct xencons_info *xencons = vtermno_to_xencons(vtermno); + unsigned int eoiflag = 0; + if (xencons == NULL) return -EINVAL; intf = xencons->intf; @@ -157,7 +161,27 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len) mb(); /* read ring before consuming */ intf->in_cons = cons; - notify_daemon(xencons); + /* + * When to mark interrupt having been spurious: + * - there was no new data to be read, and + * - the backend did not consume some output bytes, and + * - the previous round with no read data didn't see consumed bytes + * (we might have a race with an interrupt being in flight while + * updating xencons->out_cons, so account for that by allowing one + * round without any visible reason) + */ + if (intf->out_cons != xencons->out_cons) { + xencons->out_cons = intf->out_cons; + xencons->out_cons_same = 0; + } + if (recv) { + notify_daemon(xencons); + } else if (xencons->out_cons_same++ > 1) { + eoiflag = XEN_EOI_FLAG_SPURIOUS; + } + + xen_irq_lateeoi(xencons->irq, eoiflag); + return recv; } @@ -386,7 +410,7 @@ static int xencons_connect_backend(struct xenbus_device *dev, if (ret) return ret; info->evtchn = evtchn; - irq = bind_evtchn_to_irq(evtchn); + irq = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn); if (irq < 0) return irq; info->irq = irq; @@ -551,7 +575,7 @@ static int __init xen_hvc_init(void) return r; info = vtermno_to_xencons(HVC_COOKIE); - info->irq = bind_evtchn_to_irq(info->evtchn); + info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn); } if (info->irq < 0) info->irq = 0; /* NO_IRQ */ diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c index f1324fe99378..92e3433276f8 100644 --- a/drivers/tty/serdev/core.c +++ b/drivers/tty/serdev/core.c @@ -727,10 +727,24 @@ static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level, static int acpi_serdev_register_devices(struct serdev_controller *ctrl) { acpi_status status; + bool skip; + int ret; if (!has_acpi_companion(ctrl->dev.parent)) return -ENODEV; + /* + * Skip registration on boards where the ACPI tables are known to + * contain buggy devices. Note serdev_controller_add() must still + * succeed in this case, so that the proper serdev devices can be + * added "manually" later. + */ + ret = acpi_quirk_skip_serdev_enumeration(ctrl->dev.parent, &skip); + if (ret) + return ret; + if (skip) + return 0; + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, SERDEV_ACPI_MAX_SCAN_DEPTH, acpi_serdev_add_device, NULL, ctrl, NULL); |