Re: wireless dongle causing entire machine to hang

[Stanislaw Gruszka]

On Wed, Aug 15, 2018 at 10:25:48PM -0600, Randy Oostdyk wrote:
> Sorry about the mangled log file! Here's the txt file as an
> attachment, hope it's useful.

We loop infinitely in rt2x00_rxdone because we can not submit
urb. We always get EPROTO error. I think usb host driver should
give ENODEV at some point, but this is out of tree dwc_otg driver,
so I don't expect we can get fix for it.

I prepared a patch that count EPROTO errors and if it's bigger
than 10 mark device as gone. It should not make a problem
when we will get one time random error.  I'm attaching it,
please test.

Thanks
Stanislaw


diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00.h 
b/drivers/net/wireless/ralink/rt2x00/rt2x00.h
index a279a43..2689bca 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00.h
@@ -1014,6 +1014,7 @@ struct rt2x00_dev {
        unsigned int extra_tx_headroom;
 
        struct usb_anchor *anchor;
+       unsigned int num_proto_errs;
 
        /* Clock for System On Chip devices. */
        struct clk *clk;
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c 
b/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c
index 086aad2..3607b28 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c
@@ -31,6 +31,22 @@
 #include "rt2x00.h"
 #include "rt2x00usb.h"
 
+static bool rt2x00usb_check_usb_error(struct rt2x00_dev *rt2x00dev, int status)
+{
+       if (status == -ENODEV || status == -ENOENT)
+               return true;
+       
+       if (status == -EPROTO)
+               rt2x00_dev->num_proto_errs++;
+       else
+               rt2x00_dev->num_proto_errs = 0;
+
+       if (rt2x00_dev->num_proto_errs > 10)
+               return true;
+
+       return false
+}
+
 /*
  * Interfacing with the HW.
  */
@@ -57,7 +73,7 @@ int rt2x00usb_vendor_request(struct rt2x00_dev *rt2x00dev,
                if (status >= 0)
                        return 0;
 
-               if (status == -ENODEV || status == -ENOENT) {
+               if (rt2x00usb_check_usb_error(rt2x00dev, status)) {
                        /* Device has disappeared. */
                        clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
                        break;
@@ -321,7 +337,7 @@ static bool rt2x00usb_kick_tx_entry(struct queue_entry 
*entry, void *data)
 
        status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
        if (status) {
-               if (status == -ENODEV || status == -ENOENT)
+               if (rt2x00usb_check_usb_error(rt2x00dev, status))
                        clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
                set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
                rt2x00lib_dmadone(entry);
@@ -410,7 +426,7 @@ static bool rt2x00usb_kick_rx_entry(struct queue_entry 
*entry, void *data)
 
        status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
        if (status) {
-               if (status == -ENODEV || status == -ENOENT)
+               if (rt2x00usb_check_usb_error(rt2x00dev, status))
                        clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
                set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
                rt2x00lib_dmadone(entry);