Hi Aleksander,

On Thu, 2021-10-07 at 15:04 +0200, Aleksander Morgado wrote:
> Hey all,
> 
> I'm working on a setup using a RPi CM4 based board and a Sierra
> Wireless EM9191 module, running OpenWRT 21.02 and backported mhi+wwan
> drivers (from latest 5.15 rc). The kernel also has the
> mhi_pci_dev_info entry written by Thomas, as per
> https://forum.sierrawireless.com/t/sierra-wireless-airprime-em919x-pcie-support/24927
> 
> The EM9191 is now running 02.08.01.00 (latest firmware from Sierra),
> upgraded in several steps back from the original 01.04.01.02 the
> module came with. The firmware upgrades were done with
> qmi-firmware-update and the module in USB mode  in a desktop PC.
> 
> Most of the system boots end up with the mhi driver reporting that the
> module firmware crashed in different ways:
> 
> [    7.060730] mhi-pci-generic 0000:01:00.0: MHI PCI device found:
> sierra-em919x
> [    7.067906] mhi-pci-generic 0000:01:00.0: BAR 0: assigned [mem
> 0x600000000-0x600000fff 64bit]
> [    7.076455] mhi-pci-generic 0000:01:00.0: enabling device (0000 ->
> 0002)
> [    7.083277] mhi-pci-generic 0000:01:00.0: using shared MSI
> [    7.089508] mhi mhi0: Requested to power ON
> [    7.094080] mhi mhi0: Attempting power on with EE: PASS THROUGH,
> state: SYS ERROR
> [    7.180371] mhi mhi0: local ee: INVALID_EE state: RESET device ee:
> PASS THROUGH state: SYS ERROR
> [    7.187146] mhi mhi0: Power on setup success
> [    7.187219] mhi mhi0: Handling state transition: PBL
> [    7.189165] mhi mhi0: System error detected
> [    7.189178] mhi mhi0: Device MHI is not in valid state
> [    7.189189] mhi-pci-generic 0000:01:00.0: firmware crashed (7)
> [    7.213682] mhi mhi0: Handling state transition: SYS ERROR
> [    7.219183] mhi mhi0: Transitioning from PM state: Linkdown or
> Error Fatal Detect to: SYS ERROR Process
> [    7.228590] mhi-pci-generic 0000:01:00.0: firmware crashed (6)
> [    7.234429] mhi mhi0: Failed to transition from PM state: Linkdown
> or Error Fatal Detect to: SYS ERROR Process
> [    7.244433] mhi mhi0: Exiting with PM state: Linkdown or Error
> Fatal Detect, MHI state: RESET
> [    7.252963] mhi mhi0: Handling state transition: DISABLE
> [    7.258278] mhi mhi0: Processing disable transition with PM state:
> Linkdown or Error Fatal Detect
> [    7.267155] mhi mhi0: Waiting for all pending event ring processing
> to complete
> [    7.274480] mhi mhi0: Waiting for all pending threads to complete
> [    7.280576] mhi mhi0: Reset all active channels and remove MHI
> devices
> [    7.287110] mhi mhi0: Resetting EV CTXT and CMD CTXT
> [    7.292077] mhi mhi0: Exiting with PM state: DISABLE, MHI state:
> RESET
> [    7.298683] mhi-pci-generic 0000:01:00.0: failed to power up MHI
> controller
> [    7.306184] mhi-pci-generic: probe of 0000:01:00.0 failed with error
> -110
> 
> Some of the boots successfully finish and I can talk to both the QMI
> and MBIM ports exposed by the WWAN subsystem, but the success rate is
> extremely low.
> 
> Thomas, are you seeing similar issues in your setup?

On our setup, using i.MX6DL based board and a PCIe Sierra Wireless
EM9190 module, running Yocto and Linux 5.13, we don't have much success
for the moment, qmi and mbim commands very often end in timeout.

Otherwise, when responses are received, we also can observe strange
things: unexpected messages, response to previous commands or queue
buffer issue.

Moreover, AT commands and the firmware update seem to work fine.

I updated the topic opened on the Sierra Wireless forum, with our
latest progress and as well as additional information.

In addition, we observed some strange behavior of the EM919x after warm
reboots.

Best regards,
Thomas

> 

-- 
Thomas Perrot, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com