src/patches/backports/backports-linux-upstream-1.patch

   1 From 5bb6f6e1d44aa91323857715dfddb63337f8307b Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <bjorn@mork.no>
   3 Date: Sun, 3 Jul 2016 22:24:50 +0200
   4 Subject: cdc_ncm: workaround for EM7455 "silent" data interface
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   8
   9 [ Upstream commit c086e7096170390594c425114d98172bc9aceb8a ]
  10
  11 Several Lenovo users have reported problems with their Sierra
  12 Wireless EM7455 modem. The driver has loaded successfully and
  13 the MBIM management channel has appeared to work, including
  14 establishing a connection to the mobile network. But no frames
  15 have been received over the data interface.
  16
  17 The problem affects all EM7455 and MC7455, and is assumed to
  18 affect other modems based on the same Qualcomm chipset and
  19 baseband firmware.
  20
  21 Testing narrowed the problem down to what seems to be a
  22 firmware timing bug during initialization. Adding a short sleep
  23 while probing is sufficient to make the problem disappear.
  24 Experiments have shown that 1-2 ms is too little to have any
  25 effect, while 10-20 ms is enough to reliably succeed.
  26
  27 Reported-by: Stefan Armbruster <ml001@armbruster-it.de>
  28 Reported-by: Ralph Plawetzki <ralph@purejava.org>
  29 Reported-by: Andreas Fett <andreas.fett@secunet.com>
  30 Reported-by: Rasmus Lerdorf <rasmus@lerdorf.com>
  31 Reported-by: Samo Ratnik <samo.ratnik@gmail.com>
  32 Reported-and-tested-by: Aleksander Morgado <aleksander@aleksander.es>
  33 Signed-off-by: Bjørn Mork <bjorn@mork.no>
  34 Signed-off-by: David S. Miller <davem@davemloft.net>
  35 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  36 ---
  37  drivers/net/usb/cdc_ncm.c | 7 +++++++
  38  1 file changed, 7 insertions(+)
  39
  40 diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
  41 index c663722..584504e 100644
  42 --- a/drivers/net/usb/cdc_ncm.c
  43 +++ b/drivers/net/usb/cdc_ncm.c
  44 @@ -438,6 +438,13 @@ advance:
  45         if (cdc_ncm_setup(dev))
  46                 goto error2;
  47
  48 +       /* Some firmwares need a pause here or they will silently fail
  49 +        * to set up the interface properly.  This value was decided
  50 +        * empirically on a Sierra Wireless MC7455 running 02.08.02.00
  51 +        * firmware.
  52 +        */
  53 +       usleep_range(10000, 20000);
  54 +
  55         /* configure data interface */
  56         temp = usb_set_interface(dev->udev, iface_no, data_altsetting);
  57         if (temp) {
  58 --
  59 cgit v0.12
  60