On Mon, Nov 25, 2013 at 06:15:28PM -0800, Dmitry Kunilov wrote:
> Hi everyone,
>
> As a late follow-up to the discussion that happened in June about moving
> support for most ZTE CDMA devices from option.c to zte_ev.c (where the
> decision was to "convert and see if anyone complains"), I'd like to complain
> :)
>
> We have a park of approximately thirty ZTE AC2726 EVDO modems connected to
> Broadcom-based routers running Linux-mips. After recent upgrade from ancient
> 2.6.22 to relatively modern 3.9.11, all 30 are having the same problem: pppd
> connects and Internet access works for 20 to 60 seconds, then connectivity
> drops and pppd logs an LCP timeout. After that, pppd is able to restart the
> connection and run for another 20-60 seconds.
>
> I did notice that these modems are now handled by zte_ev instead of option,
> so I went and moved all the DEVICE_INFO's back from zte_ev.c to option.c and
> also disabled zte_ev module in the kernel configuration. After this change,
> the modems work just fine, like they did on 2.6.22 - using the option
> driver.
>
> Please let me know if there is any debug info I can collect to help resolve
> this issue.
Would you mind trying the patch below (against v3.12)?
Thanks,
Johan
>From a84412903e68e9e5ae4693ddd1fa7d9c780cbd28 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Tue, 26 Nov 2013 15:26:49 +0100
Subject: [PATCH] USB: serial: zte_ev debug patch
Continue to read on errors.
Warn about failed reads and writes.
Increase zte_ev buffer sizes.
Fix race in write which could lead to (temporarily) degraded throughput
(backport of fix in Greg's usb-linus branch).
---
drivers/usb/serial/generic.c | 23 ++++++++---------------
drivers/usb/serial/zte_ev.c | 2 ++
2 files changed, 10 insertions(+), 15 deletions(-)
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 1f31e6b4c251..b5d976ae1b0d 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -176,14 +176,7 @@ retry:
return result;
}
- /* Try sending off another urb, unless in irq context (in which case
- * there will be no free urb). */
- if (!in_irq())
- goto retry;
-
- clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
-
- return 0;
+ goto retry;
}
/**
@@ -369,15 +362,15 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
urb->actual_length);
- if (urb->status) {
- dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
+ if (!urb->status) {
+ usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
+ data);
+ port->serial->type->process_read_urb(urb);
+ } else {
+ dev_warn(&port->dev, "%s - non-zero urb status: %d\n",
__func__, urb->status);
- return;
}
- usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
- port->serial->type->process_read_urb(urb);
-
/* Throttle the device if requested by tty */
spin_lock_irqsave(&port->lock, flags);
port->throttled = port->throttle_req;
@@ -406,7 +399,7 @@ void usb_serial_generic_write_bulk_callback(struct urb *urb)
spin_unlock_irqrestore(&port->lock, flags);
if (status) {
- dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
+ dev_warn(&port->dev, "%s - non-zero urb status: %d\n",
__func__, status);
spin_lock_irqsave(&port->lock, flags);
diff --git a/drivers/usb/serial/zte_ev.c b/drivers/usb/serial/zte_ev.c
index fca4c752a4ed..36152e3e2605 100644
--- a/drivers/usb/serial/zte_ev.c
+++ b/drivers/usb/serial/zte_ev.c
@@ -307,6 +307,8 @@ static struct usb_serial_driver zio_device = {
},
.id_table = id_table,
.num_ports = 1,
+ .bulk_in_size = 2048,
+ .bulk_out_size = 2048,
.open = zte_ev_usb_serial_open,
.close = zte_ev_usb_serial_close,
};
--
1.8.4.4
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