E/gps_glonass_serial( 1051): could not open gps serial device /dev/ttyGS0: Permission denied

[AlessandroSolano]

Hi! First of all thank you for your precious effort on this project.

After successfully using your driver on an Android-x86 virtual device, I'm trying to install it on my ARM Samsung Galaxy Note III (running stock Android 5.0 Lollipop).

Though I'm facing this permission error:

E/gps_glonass_serial( 1051): could not open gps serial device /dev/ttyGS0: Permission denied

Which is logged in dmesg. I already checked the device permissions and they seem correct (-rw-rw---).
What can be the cause?

[dipcore]

Hi,
Make sure It's not used by other driver or module. And try to change permissions to 666.
Did you try to execute cat /dev/ttyGS0 in the android terminal? Does it return NMEA logs?

[AlessandroSolano]

I alredy tried to set the permissions to 666 but I found them restored to original after reboot.
And yes, cat shows the NMEA sentences are correctly received over the channel.

Also, the only section in the dmesg boot log that references /dev/ttyGS0 is this:

<6>[ 11.035202] dwc3 f9200000.dwc3: gadget android_usb data soft-connect
<6>[ 11.037677] usb:: dwc3_gadget_reset_interrupt
<6>[ 11.042515] usb:: dwc3_gadget_conndone_interrupt (SS)
<6>[ 11.042557] dwc3 f9200000.dwc3: gadget android_usb data soft-disconnect
<3>[ 11.042562] usb: Disconnected in case of Super speed support
<6>[ 11.043713] dwc3 f9200000.dwc3: gadget android_usb data soft-connect
<6>[ 11.050117] android_work: android_work: did not send uevent (0 0 (null))
<6>[ 11.054105] msm_vidc: 4: Closed video instance: c3d98000
<6>[ 11.144376] usb:: dwc3_gadget_reset_interrupt
<7>[ 11.144389] usb: composite_disconnect
<6>[ 11.144429] android_work: android_work: did not send uevent (0 0 (null))
<6>[ 11.199248] usb:: dwc3_gadget_conndone_interrupt (HS)
<6>[ 11.199590] android_work: android_work: did not send uevent (0 0 (null))
<7>[ 11.214797] usb: GET_DES
<6>[ 11.215047] android_work: android_work: sent uevent USB_STATE=CONNECTED
<7>[ 11.225090] usb: GET_DES
<7>[ 11.225944] usb: set_config_number single config num=0
<7>[ 11.225953] usb: set_interface_count next_interface_id=4
<6>[ 11.231334] android_usb gadget: high-speed config #1: fe8050c8.android_usb
<7>[ 11.231434] acm ttyGS0 serial state 0003
<7>[ 11.231472] usb: SET_CON
<7>[ 11.231477] usb: set_config_number single config num=0
<6>[ 11.293773] android_work: android_work: sent uevent USB_STATE=CONFIGURED

Which just seems like the usb initialization. Unfortunately I don't know how I can figure out which drivers are using it.

[AlessandroSolano]

I suspect that this has something to do with SELinux. I will need to locate the device's policies and eventually modify them.