Sierra MC8705 modem works fine in Linux 3.10.53 (Sierra_net.c V3.2)
Using this modem on our board(imx6Q SabreSD board), it works in the field for over one year.
Last week I upgraded Linux to 3.14.28(imx_3.14.28_1.0.0_ga) (Sierra_net.c V3.2).
After that, modem is detected but it doesn't work.
# ifconfig wwan0
ifconfig: wwan0: error fetching interface information: Device not found
# dmesg | grep -e sierra -e Sierra
[ 5.009833] usbcore: registered new interface driver sierra
[ 5.016359] usbserial: USB Serial support registered for Sierra USB modem
[ 5.025902] sierra 1-1.2:1.0: Sierra USB modem converter detected
[ 5.068022] usb 1-1.2: Sierra USB modem converter now attached to ttyUSB0
[ 5.076418] sierra 1-1.2:1.1: Sierra USB modem converter detected
[ 5.085750] usb 1-1.2: Sierra USB modem converter now attached to ttyUSB1
[ 5.095794] sierra 1-1.2:1.2: Sierra USB modem converter detected
[ 5.107202] usb 1-1.2: Sierra USB modem converter now attached to ttyUSB2
[ 5.121224] sierra 1-1.2:1.3: Sierra USB modem converter detected
[ 5.132774] usb 1-1.2: Sierra USB modem converter now attached to ttyUSB3
[ 5.143377] sierra 1-1.2:1.4: Sierra USB modem converter detected
[ 5.152881] usb 1-1.2: Sierra USB modem converter now attached to ttyUSB4
# lsusb
Bus 001 Device 003: ID 1199:68a3 Sierra Wireless, Inc. MC8700 Modem
Bus 001 Device 002: ID 0424:2412 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
# cat /dev/ttyUSB3
+CREG: 2,1,"2252","014C0E9E",2
OK
*CNTI: 0,UMTS
OK
...
# dmesg | grep -e pci -e PCI
[ 0.235767] PCI: CLS 0 bytes, default 64
[ 1.403808] imx6q-pcie 1ffc000.pcie: phy link never came up
[ 1.403827] imx6q-pcie 1ffc000.pcie: Failed to bring link up!
[ 1.403858] imx6q-pcie 1ffc000.pcie: failed to initialize host
[ 1.403908] imx6q-pcie: probe of 1ffc000.pcie failed with error -22
[ 2.690746] ehci-pci: EHCI PCI platform driver
I use the same SIM card, board, modem and rootfs as I tested on Linux 3.10.53.
Yesterday I read many threads related to modem in this community, and tried below:
1. Add more delay in imx6_pcie_wait_for_link in pci-imx6.c:
change to usleep_range(100, 1000), or chang count = 10000
2. Disable CONFIG_PCI_MSI
3. Remove #address_cells; #size_cells of intc in imx6qdl.dtsi
it still no wwan0 interface.
I'm really appreciate if someone can give me some idea.
PS. Is there any official released patches for Linux imx_3.14.28_1.0.0_ga?
Thanks.
Hi jifang
for 3.14.28 one can look at solutions in
IMX6Q: Linux boot halts at PCIe config space read
Best regards
igor
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