From 1aba579f3cf51fd0fe0b4d46cc13823fd1200acb Mon Sep 17 00:00:00 2001 From: Ladislav Michl Date: Fri, 18 Nov 2016 19:11:26 +0100 Subject: [PATCH] cdc-acm: handle read pipe errors Read urbs are submitted back only on success, causing read pipe running out of urbs after few errors. No more characters can be read from tty device then until it is reopened and no errors are reported. Fix that by always submitting urbs back and clearing stall on -EPIPE. Signed-off-by: Ladislav Michl Acked-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 60 ++++++++++++++++++++++++++++++------- drivers/usb/class/cdc-acm.h | 3 ++ 2 files changed, 53 insertions(+), 10 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index cf2029464ca4..d053075a8444 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -429,27 +429,41 @@ static void acm_read_bulk_callback(struct urb *urb) dev_vdbg(&acm->data->dev, "got urb %d, len %d, status %d\n", rb->index, urb->actual_length, status); + set_bit(rb->index, &acm->read_urbs_free); + if (!acm->dev) { - set_bit(rb->index, &acm->read_urbs_free); dev_dbg(&acm->data->dev, "%s - disconnected\n", __func__); return; } - if (status) { - set_bit(rb->index, &acm->read_urbs_free); - if ((status != -ENOENT) || (urb->actual_length == 0)) - return; + switch (status) { + case 0: + usb_mark_last_busy(acm->dev); + acm_process_read_urb(acm, urb); + break; + case -EPIPE: + set_bit(EVENT_RX_STALL, &acm->flags); + schedule_work(&acm->work); + return; + case -ENOENT: + case -ECONNRESET: + case -ESHUTDOWN: + dev_dbg(&acm->data->dev, + "%s - urb shutting down with status: %d\n", + __func__, status); + return; + default: + dev_dbg(&acm->data->dev, + "%s - nonzero urb status received: %d\n", + __func__, status); + break; } - usb_mark_last_busy(acm->dev); - - acm_process_read_urb(acm, urb); /* * Unthrottle may run on another CPU which needs to see events * in the same order. Submission has an implict barrier */ smp_mb__before_atomic(); - set_bit(rb->index, &acm->read_urbs_free); /* throttle device if requested by tty */ spin_lock_irqsave(&acm->read_lock, flags); @@ -479,14 +493,30 @@ static void acm_write_bulk(struct urb *urb) spin_lock_irqsave(&acm->write_lock, flags); acm_write_done(acm, wb); spin_unlock_irqrestore(&acm->write_lock, flags); + set_bit(EVENT_TTY_WAKEUP, &acm->flags); schedule_work(&acm->work); } static void acm_softint(struct work_struct *work) { + int i; struct acm *acm = container_of(work, struct acm, work); - tty_port_tty_wakeup(&acm->port); + if (test_bit(EVENT_RX_STALL, &acm->flags)) { + if (!(usb_autopm_get_interface(acm->data))) { + for (i = 0; i < acm->rx_buflimit; i++) + usb_kill_urb(acm->read_urbs[i]); + usb_clear_halt(acm->dev, acm->in); + acm_submit_read_urbs(acm, GFP_KERNEL); + usb_autopm_put_interface(acm->data); + } + clear_bit(EVENT_RX_STALL, &acm->flags); + } + + if (test_bit(EVENT_TTY_WAKEUP, &acm->flags)) { + tty_port_tty_wakeup(&acm->port); + clear_bit(EVENT_TTY_WAKEUP, &acm->flags); + } } /* @@ -1631,6 +1661,15 @@ static int acm_reset_resume(struct usb_interface *intf) #endif /* CONFIG_PM */ +static int acm_pre_reset(struct usb_interface *intf) +{ + struct acm *acm = usb_get_intfdata(intf); + + clear_bit(EVENT_RX_STALL, &acm->flags); + + return 0; +} + #define NOKIA_PCSUITE_ACM_INFO(x) \ USB_DEVICE_AND_INTERFACE_INFO(0x0421, x, \ USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \ @@ -1872,6 +1911,7 @@ static struct usb_driver acm_driver = { .resume = acm_resume, .reset_resume = acm_reset_resume, #endif + .pre_reset = acm_pre_reset, .id_table = acm_ids, #ifdef CONFIG_PM .supports_autosuspend = 1, diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h index eca5a5f80a54..c980f11cdf56 100644 --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -103,6 +103,9 @@ struct acm { spinlock_t write_lock; struct mutex mutex; bool disconnected; + unsigned long flags; +# define EVENT_TTY_WAKEUP 0 +# define EVENT_RX_STALL 1 struct usb_cdc_line_coding line; /* bits, stop, parity */ struct work_struct work; /* work queue entry for line discipline waking up */ unsigned int ctrlin; /* input control lines (DCD, DSR, RI, break, overruns) */