Switching from generic driver to Semtech driver caused firmware failure

IoT Modules
1

We are using the EM9291 with fedora core 40 which uses the default mhi driver. We were switching to the Semtech driver, which was unsigned. We loaded the driver but ran into problems. We checked the BIOS and secure boot was enabled, so we disabled that.

Now, the driver loads, but we ran into the following message in dmesg

[3.533436] mhi-pci-sentech 0000:04:00.0: MHI PCI device found: sierra-em929x
[3.533442] mhi-pci-sentech 0000:04:00.0: BAR 0 [mem 0x51501000-0x51501fff 64bit]: assigned
[3.533464] mhi-pci-semtech 0000:04:00.0: enabling device (0000 -> 0002)
[3.539341] mhi mhi0: Requested to power ON
[3.539353] mhi mhi0: Power on setup success
[3.539429] mhi mhi0: No firmware image defined or !sbl_size || !seg_len
[3.5402851 mhi-pci-semtech 0000:04:00.0: failed to power up MHI controller
[3.541604] mhi-pci-semtech 0000:04:00.0: probe with driver mhi-pci-semtech failed with error -110

Is there a way to reload the device firmware?

The device shows in lspci, but does not show up in /dev. It also does not show up if we load Windows with the Semtech drivers.

2

see if this discussion thread helps:

I can see it has the same error message “failed to power up MHI controller”

3

This resolved itself after a few hours of being off. The modem is working again.

Is the boot load process documented? Is there a period we should avoid removing power?

4

do you mean the module back to workable with MBPL PCIe driver after cutting power for a few hours?
Then it seems to be a hardware issue…