Mainline kernel (4.5.3) MMC and SD problems (Apalais T30/Apalis T30 Eval board)

Hi All,
I’ve successfully compiled the latest stable kernel for apalis 30 (and patched the eth driver to support igb_mac).
After booting the kernel and the mainline apalis-eval dtb file, I cannot use the eval board MMC and SD sockets. The MMC/SD drivers fail with initialization error (BTW, it seems to detect the cards).

I know the 3.1.10 Toradex BSP contains gpio drive level and slew rate tweaking on the pins, but it is not present in the 4.5.3 dts files.

Similar issue with the PCIe switch on the eval board, how can I add the reset function to the dts file?

Best regards,
Zoltan

Hi Zoltan

Nice to hear from more customers interested in running mainline on our modules.

I doubt it has much to do with drive strength and/or slew rate settings but rather with most modern cards attempting to switch signalling voltage which is currently neither properly disabled (e.g. for pre V1.1A modules resp. the SD1 slot) nor enabled (e.g. for MMC1 slot starting with V1.1A modules). I am currently testing a few patches which should hopefully fix this. That said it really depends on the cards tried. Older regular SD cards should already work just fine.

Concerning the PCIe switch unfortunately there exists still no generic power/reset sequencing framework in Linux so a simple devie tree update won’t do. For the time being it might be easier to do this in the boot loader which I can post a patch for as well.

Cheers

Marcel Ziswiler

Platform Manager Embedded Linux

Hi Marcel,
Thanks for your reply! We’d really prefer the mainline kernel over the 3.1.10 for the T30 :slight_smile:

The reason I’ve started to work with the mainline kernel is that we had some strange problems with atheros 9k cards (mini pci-e). If we switch to monitor mode and ifconfig them up, after 5-100seconds the linux will freeze totally (not kernel panic, but frozen death). I was hoping that the latest kernel fixes this problem, but unfortunately not. I’ve tried 3.1.10, and then backporting the wireless drivers, but all of them fail the same way, including the 4.5.3 kernel.
I’ve tried the apalis eval board amd the Ixora carrier board, but the same result.

Have you ever seen any strange freezes on the pci-e bus (atheros or any other pcie device)? BTW We’ve just ordered 100+ T30 modules, so I hope it is not a more serious problem :slight_smile:

I would appreciate any patch or pointer you can post or send me to fix my SD/MMC card issue or the PCI switch reset.

Best regards,

Zoltan

Hi Zoltan

Just note that there won’t be any hardware accelerated graphics/multimedia stacks available for mainline plus some peripherals are still missing mainline support (e.g. audio, camera, SATA, USB device et. al.).

No, we haven’t really seen any such PCIe freezes. After all gigabit Ethernet works rock solid.

Concerning SD/MMC have a look here. Concerning PCIe switch reset here.

Cheers

Marcel Ziswiler

Platform Manager Embedded Linux

Hi Marcel,

Thanks for the patches!

Do I have to worry about not writing the register into the PEX switch to force 2.5G mode (like the 3.1.10 BSP does)?

We are still having thise freezes on our ath9k devices connected to the PEX switch on the eval board. Do you guys know about any pending issue with the PCie lane on the SOM (to the eval board), PEX switch driver or T30 pci driver?

Thanks again!
Zoltan